IS5213 Data Science and Big Data Solutions

The following is the frequency distribution for the speeds of a sample of automobiles traveling on an interstate highway.

Speed (mph)	Frequency
50−54	2
55−59	4
60−64	5
65−69	10
70−74	9
75−79	5
	35

The standard deviation is _____.

a. 6.969

b. 50.000

c. 7.071

d. 48.570

 Data collected over several time periods are _____ data.

a. cross-sectional

b. time dependent

c. time-controlled

d. time series

The expression used to compute an interval estimate of μ may depend on any of the following factors EXCEPT _____.

a. whether the population has an approximately normal distribution

b. the sample size

c. whether the population standard deviation is known

d. whether there is sampling error

uppose annual salaries for sales associates from Hayley's Heirlooms have a bell-shaped distribution with a mean of $32,500 and a standard deviation of $500.



The z-score for a sales associate from this store who earns $33,500 is _____.

a. −2

b. 33.5

c. 2

d. 0.97

The z value for a 97.8% confidence interval estimation is _____.

a. 1.96

b. 2.29

c. 2.00

d. 2.02

If the data distribution is symmetric, the skewness is _____.

a. .5

b. 1

c. 0

d. –.5

Flight time from Cincinnati to Atlanta is an example of a _____ variable and _____ measurement.

a. continuous; interval

b. discrete; interval

c. discrete; ratio

d. continuous; ratio

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 percentage of workers who took 0−5 sick days per month is _____.

a. 120%

b. 75%

c. 60%

d. 20%

Which of the following is NOT a measure of variability of a single variable?

a. standard deviation

b. range

c. coefficient of variation

d. covariance

t is known that the variance of a population equals 1,936. A random sample of 121 has been selected from the population. There is a .95 probability that the sample mean will provide a margin of error of _____.

a. 344.96 or less

b. 31.36 or less

c. 1,936 or less

d. 7.84 or less

Suppose annual salaries for sales associates from Hayley's Heirlooms have a bell-shaped distribution with a mean of $31,500 and a standard deviation of $500.



The z-score for a sales associate from this store who earns $30,650 is _____.

a. 1.7

b. −1.7

c. 30.65

d. 0.97

In the textile industry, a manufacturer is interested in the number of blemishes or flaws occurring in each 100 feet of material. The probability distribution that has the greatest chance of applying to this situation is the _____.

a. binomial distribution

b. normal distribution

c. uniform distribution

d. Poisson distribution

Assume z is a standard normal random variable. Then P(1.45 ≤ z ≤ 2.31) equals _____.

a. 0.9160

b. 0.9369

c. 0.0631

d. 0.4160

The correlation coefficient _____.

a. can be larger than 1

b. cannot be larger than 1

c. cannot be negative

d. is the same as the covariance

A random sample of 100 people was taken. There were sixty people in the sample who favored Candidate A. We are interested in determining whether or not the proportion of the population in favor of Candidate A is significantly more than 50%.

The test statistic is   _____.

a. 2.24

b. 1.29

c. 2.00

d. 4.00

Which of the following is a required condition for a discrete probability function?

a. f(x) < 0

b. Σf(x) = 0

c. Σf(x) = 1

d. f(x) ≥ 1 for all values of x

In hypothesis testing, the alternative hypothesis is _____.

a. the maximum probability of a Type I error

b. the hypothesis concluded to be true if the null hypothesis is rejected

c. the hypothesis tentatively assumed true in the hypothesis-testing procedure

d. the maximum probability of a Type II error

If A and B are mutually exclusive, then _____.

a. P(A ∩ B) = 1

b. P(A) + P(B) = 1

c. P(A ∩ B) = 0

d. P(A) + P(B) = 0

There are 20 boys and 8 girls in a class. What type of graph can be used to display this information?

a. stem-and-leaf plot

b. scatter diagram

c. histogram

d. bar graph

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 cumulative relative frequency for the class of 11−15 is _____.

a. 199

b. .995

c. .07

d. 1

When the results of experimentation or historical data are used to assign probability values, the method used to assign probabilities is referred to as the _____.

a. relative frequency method

b. subjective method

c. classical method

d. posterior method

The number of customers who enter a store during one day is an example of _____.

a. a discrete random variable

b. a continuous random variable

c. either a continuous or a discrete random variable, depending on the number of the customers

d. either a continuous or a discrete random variable, depending on the gender of the customers

The sample variance _____.

a. is always larger than the true value of the population variance

b. can never be zero

c. is always smaller than the true value of the population variance

d. could be smaller, equal to, or larger than the true value of the population variance

There is a lower limit but no upper limit for a random variable that follows the _____ probability distribution.

a. normal

b. uniform

c. binomial

d. exponential

A sample of 2,500 people was asked how many cups of coffee they drink in the morning. You are given the following sample information.

Cups of Coffee	Frequency
0	700
1	900
2	600
3	300
	2,500

The variance of the number of cups of coffee is _____.

a. 2.4

b. .96

c. 1

d. .9798