Exhibit 8-3
A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph.
Refer to Exhibit 8-3. The 86.9% confidence interval for μ is _____.
A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph.
Refer to Exhibit 8-3. The 86.9% confidence interval for μ is _____.
A random sample of 16 students selected from the student body of a large university had an average age of 23 years. We want to determine if the average age of all the students at the university is significantly different from 21. Assume the distribution of the population of ages is normal with a standard deviation of 4 years.
At a 0.05 level of significance, it can be concluded that the mean age is _____.
At a 0.05 level of significance, it can be concluded that the mean age is _____.
The probability distribution of all possible values of the sample mean is called the ____.
Exhibit 3-2
A researcher has collected the following sample data. The mean of the sample is 5.
The range is _____.
A researcher has collected the following sample data. The mean of the sample is 5.
| 3 | 5 | 12 | 3 | 2 |
The range is _____.
Random samples of size 100 are taken from a process (an infinite population) whose population proportion is .2. The mean and standard deviation of the distribution of sample proportions are _____.
The probability Pete will catch fish when he goes fishing is 0.6. Pete is going fishing 4 days next week.
The probability that Pete will catch fish on 1 or fewer days is _____.
The probability that Pete will catch fish on 1 or fewer days is _____.
Excel's _____ function can be used to compute the sample correlation coefficient.
The numbers of hours worked (per week) by 390 statistics students are shown below.
The midpoint of the last class is _____.
| Number of Hours | Frequency | |||
| 0 ≤ x < 20 | 20 | |||
| 20 ≤ x < 40 | 100 | |||
| 40 ≤ x < 60 | 180 | |||
| 60 ≤ x < 80 | 90 | |||
The midpoint of the last class is _____.
An auto manufacturer wants to estimate the annual income of owners of a particular model of automobile. A random sample of 200 current owners is selected. The population standard deviation is known. Which Excel function would NOT be appropriate to use to construct a confidence interval estimate?
Exhibit 5-4
A local bottling company has determined the number of machine breakdowns per month and their respective probabilities as shown below.
The expected number of machine breakdowns per month is _____.
A local bottling company has determined the number of machine breakdowns per month and their respective probabilities as shown below.
| Number of | |
| Breakdowns | Probability |
| 0 | .12 |
| 1 | .38 |
| 2 | .25 |
| 3 | .18 |
| 4 | .07 |
The expected number of machine breakdowns per month is _____.
If the margin of error in an interval estimate of μ is 4.8, the interval estimate equals _____.
If P(A) = 0.74, P(A ∪ B) = 0.82, and P(A ∩ B) = 0.58, then P(B) = _____.
If an interval estimate is said to be constructed at the 90% confidence level, the confidence coefficient would be _____.
Categorical data _____.
An experiment consists of tossing four coins successively. The number of sample points in this experiment is 16
What is the difference between a bar graph and a histogram?
If P(A) = 0.67, P(B) = 0.59, and P(A ∪ B) = 0.80, then P(B | A) = _____.
Exhibit 2-3
The number of sick days taken (per month) by 200 factory workers is summarized below.
The number of workers who took more than 10 sick days per month is _____.
The number of sick days taken (per month) by 200 factory workers is summarized below.
| Number of Days | Frequency | |||
| 0 − 5 | 120 | |||
| 6 − 10 | 65 | |||
| 11 − 15 | 14 | |||
| 16 − 20 | 1 | |||
The number of workers who took more than 10 sick days per month is _____.
For a standard normal distribution, the probability of obtaining a z value between –2.4 and –2.0 is _____.
A random sample of 144 bottles of cologne showed an average content of 5 ounces. It is known that the standard deviation of the contents (i.e., of the population) is 0.48 ounces.
The point estimate of the mean content of all bottles is _____.
The point estimate of the mean content of all bottles is _____.
The numbers of hours worked (per week) by 400 statistics students are shown below.
| Number of Hours | Frequency | |||
| 0 ≤ x < 10 | 10 | |||
| 10 ≤ x < 20 | 60 | |||
| 20 ≤ x < 30 | 210 | |||
| 30 ≤ x < 40 | 120 | |||
The class width for this distribution _____.
The binomial probability distribution is used with _____.
If the mean of a normal distribution is negative, _____.
To estimate a population mean, the sample size needed to provide a margin of error of 3 or less with a 0.95 probability when the population standard deviation equals 16 is _____.
A numerical description of the outcome of an experiment is called a _____.
In general, higher confidence levels provide _____.
When using Excel's POISSON.DIST function, one should choose TRUE for the third input if _____.
Consider the following.
Assume the population is normally distributed.
The p-value is equal to _____.
| n = 25 | H0: μ ≥ 70 | |
| x̄ = 66.508 | Ha: μ < 70 | |
| σ = 7.746 |
Assume the population is normally distributed.
The p-value is equal to _____.
Events A and B are mutually exclusive. Which of the following statements is also true?
A random sample of 25 statistics examinations was selected. The average score in the sample was 76 with a variance of 144. Assuming the scores are normally distributed, the 99% confidence interval for the population average examination score is _____.
Exhibit 6-7
f(x) = (1/10) e-x/10 x ≥ 0
Refer to Exhibit 6-7. The probability that x is less than 5 is _____.
f(x) = (1/10) e-x/10 x ≥ 0
Refer to Exhibit 6-7. The probability that x is less than 5 is _____.
Exhibit 2-3
The number of sick days taken (per month) by 200 factory workers is summarized below.
The relative frequency of workers who took 10 or fewer sick days is _____.
The number of sick days taken (per month) by 200 factory workers is summarized below.
| Number of Days | Frequency | |||
| 0 − 5 | 120 | |||
| 6 − 10 | 65 | |||
| 11 − 15 | 14 | |||
| 16 − 20 | 1 | |||
The relative frequency of workers who took 10 or fewer sick days is _____.
Which of the following symbols represents the mean of a sample?
For a one-tailed test (lower tail) with a sample size of 10 and a .10 level of significance the t value is _____.
Exhibit 8-3
A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph.
Refer to Exhibit 8-3. The value to use for the standard error of the mean is _____.
A random sample of 81 automobiles traveling on a section of an interstate showed an average speed of 60 mph. The distribution of speeds of all cars on this section of highway is normally distributed, with a standard deviation of 13.5 mph.
Refer to Exhibit 8-3. The value to use for the standard error of the mean is _____.
Exhibit 5-5
AMR is a computer-consulting firm. The number of new clients that it has obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below.
The variance is _____.
AMR is a computer-consulting firm. The number of new clients that it has obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below.
| Number of | |
| New Clients | Probability |
| 0 | .05 |
| 1 | .10 |
| 2 | .15 |
| 3 | .35 |
| 4 | .20 |
| 5 | .10 |
| 6 | .05 |
The variance is _____.
Of five letters (A, B, C, D, and E), two letters are to be selected at random. How many possible selections are there?
A large university consists of 65% of students who are 20 years of age or older. A random sample of 9 students is selected.
What is the probability that among the students in the sample exactly three are 20 or older?
What is the probability that among the students in the sample exactly three are 20 or older?
A large university consists of 65% of students who are 20 years of age or older. A random sample of 9 students is selected.
What is the probability that among the students in the sample exactly three are 20 or older?
What is the probability that among the students in the sample exactly three are 20 or older?
Exhibit 5-5
AMR is a computer-consulting firm. The number of new clients that it has obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below.
The standard deviation is _____.
AMR is a computer-consulting firm. The number of new clients that it has obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below.
| Number of | |
| New Clients | Probability |
| 0 | .05 |
| 1 | .10 |
| 2 | .15 |
| 3 | .35 |
| 4 | .20 |
| 5 | .10 |
| 6 | .05 |
The standard deviation is _____.
A sample statistic, such as x̄, that estimates the value of the corresponding population parameter is known as a _____.
Exhibit 6-7
f(x) = (1/10) e-x/10 x ≥ 0
Refer to Exhibit 6-7. The probability that x is between 3 and 6 is _____.
f(x) = (1/10) e-x/10 x ≥ 0
Refer to Exhibit 6-7. The probability that x is between 3 and 6 is _____.
The sampling distribution of the sample mean _____.
If P(A) = 0.5, P(B) = 0.25, and P(A ∩ B) = 0.2, then P(B | A) =_____.
A population of size 1,000 has a proportion of .5. Therefore, the proportion and the standard deviation of the sample proportion for samples of size 100 are _____.
The value of the sum of the squared deviations from the mean, i.e., Σ(x − x̄)2 must always be _____.
The symbol σ is used to represent the _____.
The interquartile range is _____.
A continuous random variable may assume _____.
An estimate of a population parameter that provides an interval believed to contain the value of the parameter is known as the _____.
The starting salaries of individuals with an MBA degree are normally distributed with a mean of $45,000 and a standard deviation of $7,000. What percentage of MBAs will have starting salaries of $35,000 to $55,000?
If X and Y are mutually exclusive events with P(X) = 0.375, P(Y) = 0.34, then P(X ∩ Y) = _____.
Excel's RAND function _____.
A graphical presentation of a frequency distribution, relative frequency distribution, or percent frequency distribution of quantitative data constructed by placing the class intervals on the horizontal axis and the frequencies on the vertical axis is a _____.
A researcher has collected the following sample data.
The median is _____.
| 3 | 11 | 7 | 10 | 7 |
| 4 | 8 | 3 | 10 | 5 |
The median is _____.
The standard deviation of a binomial distribution is _____.
Exhibit 3-2
A researcher has collected the following sample data. The mean of the sample is 5.
The coefficient of variation is _____.
A researcher has collected the following sample data. The mean of the sample is 5.
| 3 | 5 | 12 | 3 | 2 |
The coefficient of variation is _____.
The starting salaries of individuals with an MBA degree are normally distributed with a mean of $35,000 and a standard deviation of $8,000. What percentage of MBAs will have starting salaries of $24,000 to $46,000?
As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution _____.
The assembly time for a product is uniformly distributed between 6 and 10 minutes. The probability of assembling the product in less than 6 minutes is _____.
In an experiment, events A and B are mutually exclusive. If P(A) = .6, then the probability of B _____.
If r = 0.48 for data set A and r = −0.48 for data set B, which of the following is true?
Probability Distribution
The variance of x equals _____.
| x | f(x) |
| 10 | .2 |
| 20 | .3 |
| 30 | .4 |
| 40 | .1 |
The variance of x equals _____.
The z value for a 97.8% confidence interval estimation is _____.
A population of size 1,000 has a proportion of .5. Therefore, the proportion and the standard deviation of the sample proportion for samples of size 100 are _____.
The random variable x is the number of occurrences of an event over an interval of 10 minutes. It can be assumed the probability of an occurrence is the same in any two time periods of an equal length. It is known that the mean number of occurrences in 10 minutes is 5.3.
The probability there are less than 3 occurrences is _____.
The probability there are less than 3 occurrences is _____.
Random samples of size 36 are taken from a population that has 400 elements, a mean of 170, and a variance of 144. The distribution of the population is unknown. The mean and the standard error of the distribution of sample means are _____.
The probability distribution for the number of goals the Lions soccer team makes per game is given below.
What is the probability that in a given game the Lions will score at least 1 goal?
| Number of Goals | Probability |
| 0 | 0.10 |
| 1 | 0.15 |
| 2 | 0.35 |
| 3 | 0.30 |
| 4 | 0.10 |
What is the probability that in a given game the Lions will score at least 1 goal?
Which of the following properties of a binomial experiment is called the stationarity assumption?
Which of the following is NOT a required condition for a discrete probability function?
Which of the following graphical methods is most appropriate for categorical data?
Suppose x is a normally distributed random variable with a mean of 10 and a standard deviation of 5. The probability that x is between 1.87 and 19.78 is _____.
Random samples of size 100 are taken from a process (an infinite population) whose population proportion is .2. The mean and standard deviation of the distribution of sample proportions are _____.
A sample statistic, such as x̄, that estimates the value of the corresponding population parameter is known as a _____.
In the hypothesis testing procedure, α is _____.
Consider the continuous random variable x, which has a uniform distribution over the interval from 20 to 28.
Refer to Exhibit 6-1. The variance of x is approximately _____.
Refer to Exhibit 6-1. The variance of x is approximately _____.
A student believes that the average grade on the final examination in statistics is at least 85. She plans on taking a sample to test her belief. The correct set of hypotheses is _____.
Which of the following statements about a discrete random variable and its probability distribution is true?
Which of the following symbols represents the size of a population?
The manager of a grocery store has selected a random sample of 100 customers. The average length of time it took these 100 customers to check out was 3.0 minutes. It is known that the standard deviation of the checkout time is 1 minute.
Refer to Exhibit 8-2. If the confidence coefficient is reduced to .80, the standard error of the mean _____.
Refer to Exhibit 8-2. If the confidence coefficient is reduced to .80, the standard error of the mean _____.
The manager of a grocery store has selected a random sample of 100 customers. The average length of time it took these 100 customers to check out was 5.0 minutes. It is known that the standard deviation of the checkout time is 4 minutes.
The standard error of the mean equals _____.
The standard error of the mean equals _____.
A probability distribution showing the probability of x successes in n trials, where the probability of success does not change from trial to trial, is termed a _____.
Consider the continuous random variable x, which has a uniform distribution over the interval from 20 to 28.
Refer to Exhibit 6-1. The probability that x will take on a value of at least 26 is _____.
Refer to Exhibit 6-1. The probability that x will take on a value of at least 26 is _____.
The interquartile range is used as a measure of variability to overcome what difficulty of the range?
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