1) Most Companies That Make Golf Balls and Golf Clubs Use a One-Armed Robot Named Iron Byron To
1) Most companies that make golf balls and golf clubs use a one-armed robot named "Iron Byron" to
test their balls for length and accuracy, but because of swing variations by real golfers, these test
robots don't always indicate how the clubs will perform in actual use. One company in the golfing
industry is interested in testing its new driver to see if it has greater length off the tee than the
best-selling driver. To do this, it has selected a group of golfers of differing abilities and ages. Its
plan is to have each player use each of the two clubs and hit five balls. It will record the average
length of the drives with each club for each player. The resulting data for a sample of 10 players
are:
Player New Club Leading Club
1 236.4 237.2
2 202.5 200.4
3 245.6 240.8
4 257.4 259.3
5 223.5 218.9
6 205.3 200.6
7 266.7 258.9
8 240 236.5
9 278.9 280.5
10 211.4 206.5
What is an appropriate null hypothesis to be tested?
A) Ho: μd ≤ 0 B) Ho: μ1 = μ2 C) Ho: μ1 ≥ μ2 D) Ho: μD = 0
2) If a manager wishes to develop a confidence interval estimate for estimating the difference between
two population means, an increase in the size of the samples used will result in:
A) a less precise confidence interval
B) a wider confidence interval.
C) a more precise confidence interval.
D) an increase in the size of the critical value.
3) Which distribution is used in testing the hypotheses about the equality of two population
variances?
A) z-distribution B) t-distribution C) x2 distribution D) F-distribution
4) When conducting a one-tailed hypothesis test of a population variance using a sample size of n =
24 and a 0.10 level of significance, the critical value is:
A) 36.4150. B) 33.1962. C) 35.1725. D) 32.0069.
5) A hotel chain has four hotels in Oregon. The general manager is interested in determining whether
the mean length of stay is the same or different for the four hotels. She selects a random sample of n
= 20 guests at each hotel and determines the number of nights they stayed. Assuming that she plans
to test this using an alpha level equal to 0.05, which of the following is the correct critical value?
A) F = 2.56 B) F = 3.04 C) t = 1.9917 D) F = 2.76
6) A walk-in medical clinic believes that arrivals are uniformly distributed over weekdays (Monday
through Friday). It has collected the following data based on a random sample of 100 days.
Frequency
Mon 25
Tue 22
Wed 19
Thu 18
Fri 16
Total 100
To conduct a goodness-of-fit test, what is the expected value for Friday?
A) 16 B) 20 C) 25 D) 100
7) A recent study of 15 shoppers showed that the correlation between the time spent in the store and
the dollars spent was 0.235. Using a significance level equal to 0.05, which of the following is the
appropriate null hypothesis to test whether the population correlation is zero?
A) Ho : μ = 0.0 B) Ho : p≠ 0 C) Ho : r = 0.0 D) Ho : p = 0.0
8) The editors of a national automotive magazine recently studied 30 different automobiles sold in the
United States with the intent of seeing whether they could develop a multiple regression model to
explain the variation in highway miles per gallon. A number of different independent variables
were collected. The following regression output (with some values missing) was recently presented
to the editors by the magazine's analysts:
Based on this output and your understanding of multiple regression analysis, how many degrees of
freedom are associated with the Residual in the ANOVA table?
A) 19 B) 7 C) 29 D) 22
9) To increase productivity, workers went through a training program. The management wanted to
know the effectiveness of the program. A sample of seven workers was taken and their daily
production rates before and after the training are shown below.
Worker Before After
1 18 22
2 23 25
3 25 27
4 22 25
5 20 24
6 21 19
7 19 20
Based on the data, the training program is
A) ineffective. B) effective.
C) neither effective nor ineffective. D) none of the above.
10) If the variance of the contents of cans of orange juice is significantly more than 0.003, the manager
has to order to stop the filling machine. A sample of 26 cans of orange juice showed a standard
deviation of 0.06 ounces. Based on the sample and at the 0.05 level of significance, the filling
machine should be
A) kept going. B) upgraded. C) stopped. D) downgraded.
11) In a one-way design, which of the following is true?
A) The sample sizes must be equal.
B) The sample sizes must all differ.
C) The mean squares between will be larger than the mean squares within if the null hypothesis
is rejected.
D) The populations must have equal means.
12) Many companies use well-known celebrities as spokespeople in their TV advertisements. A study
was conducted to determine whether brand awareness of female TV viewers and the gender of the
spokesperson are independent. Each in a sample of 300 female TV viewers was asked to identify a
product advertised by a celebrity spokesperson. The gender of the spokesperson and whether or
not the viewer could identify the product was recorded. The numbers in each category are given
below.
Male Celebrity Female Celebrity
Identified product 41 61
Cound not identify 109 89
Referring to these sample data, if the appropriate null hypothesis is tested using a significance level
equal to .05, which of the following conclusions should be reached?
A) The mean number of products identified for males is different than the mean number for
females.
B) There is a relationship between gender of the celebrity and product identification.
C) Females have higher brand awareness than males.
D) There is no relationship between gender of the celebrity and product identification.
13) Which of the following is NOT an assumption for the simple linear regression model?
A) The individual error terms are statistically independent.
B) The mean of the dependent variable value for all levels of x can be connected by a straight
line.
C) The error terms have equal variances for all values of the independent variable.
D) The distribution of the error terms will be skewed left or right depending on the shape of the
dependent variable.
14) Consider the following residual plot.
Given this plot, what conclusion should be reached?
A) The assumption of constant variance seems to be supported by this plot.
B) There appears to be no basis for concluding that the relationship between the x and y variable
is not linear.
C) Both A and B are true.
D) Neither A nor B are true.
15) Given the following information, calculate the degrees of freedom that should be used in the
pooled-standard deviation t-test.
s1^2 = 4 s2^2 = 6
n1 = 16 n2 = 25
A) df = 25 B) df = 39 C) df = 41 D) df = 16
TRUE/FALSE.
16) A direct retailer that sells clothing on the Internet has two distribution centers and wants to
determine if there is a difference between the proportion of customer order shipments that contain
errors (wrong color, wrong size, etc.). It takes a sample of orders from each distribution center and
obtain the following results:
Distribution Center 1 Distribution Center 2
Number of orders 120 145
Number or errors 4 6
Based on these data it can proceed with assuming the normal distribution for each of the
proportion sampling distributions.
16) True/False
17) The F-distribution can only have positive values.
17) True/False
18) Three brands of running shoes are each tested by 10 different runners. The amount of wear on the
sole of the shoes is then measured. The objective is to determine if there is any difference among the
three brands of shoes based on how long the soles last. The null hypothesis is:
Ho : μ1 = μ2 = μ3.
18) True/False
19) A study was recently done in the United States in which car owners were asked to indicate whether
their most recent car purchase was a U.S. car, a German car, or a Japanese car. The people in the
survey were divided by geographic region in the United States. The following data were recorded.
US Japanese German
East Coast 200 200 50
Central 250 100 20
West Coast 80 300 40
Given this situation, to test whether the car origin is independent of the geographical location of the
buyer, the critical value for alpha = .10 is 14.6837.
19) True/False
20) If the sample value of the intercept turns out to be an illogical value, this is acceptable as long as x =
0 is not within the range of the data.
20)True/False