STAT 1450 Study Guide - Final Guide: Nasal Spray, Confidence Interval, Dependent And Independent Variables
9 Oct 2018
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STAT 1450 – FINAL EXAM REVIEW
Note: This review is longer than a final exam would be, but the questions are representative of the types of
questions you could see. There are no guarantees that the final exam “looks like” the final exam review.
**Multiple Choice** Please circle the best answer.
1. After conducting a survey at a pet store to see what impact having a pet had on the condition of the yard, a
news reporter stated, “There appears to be a strong correlation between owning a pet and the condition of the
yard.” This statement means
a. that if a home owner owns a pet, the better the condition of the yard.
b. that if a home owner owns a pet , the worse the condition of the yard.
c. that there is a strong relationship between the pet ownership and the condition of the yard, but we do not
know if this relationship is positive or negative.
d. nothing, since owning a pet and condition of the yard are categorical variables.
2. Suppose a particular outcome from a random event has a probability of 0.02. Which of the following
statements represent correct interpretations of this probability?
a. The outcome will never happen.
b. The outcome will certainly happen two times out of every 100 trials.
c. The outcome is expected to happen about two times out of every 100 trials.
d. The outcome could happen, or it couldn't, the chances of either result are the same.
3. A recent article in an educational research journal reports a correlation of +0.8 between math achievement
and overall math aptitude for a large sample of students. It also reports a correlation of -0.8 between math
achievement and a math anxiety test for the same group of students. Only students with scores on all three
measures were included in the study. Which of the following interpretations is the most correct?
a. The correlation of +0.8 indicates a stronger a relationship than the correlation of -0.8.
b. The correlation of +0.8 is just as strong as the correlation of -0.8.
c. It is impossible to tell which correlation is stronger.
4. A group of 30 introductory statistics students took a 25-item test. The mean and standard deviation were
computed; the standard deviation was 0. You know that
a. about half of the scores were above the mean
b. the test was so hard that everyone missed many of the questions
c. a calculation error must have been made in determining the standard deviation
d. everyone correctly answered the same number of items
5. Suppose we are told that X and Y have a strong correlation, but we do not know whether it is a positive or
negative correlation. The scatterplot tells us, however, that when X is below its mean, Y tends to be above its
mean, and when X is above its mean, Y tends to be below its mean. What is the sign on the correlation
coefficient in this case?
a. Positive
b. Negative
c. Zero
d. No way to tell
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6. If the characteristics of a sample approximate the characteristics of its population in every respect, the sample
is
a. accidental
b. random
c. representative
d. stratified
e. systematic
7. If a fair coin is tossed five times, which of the following ordered sequence of heads (H) and tails (T), if any, is
MOST LIKELY to occur?
a. H T H T T
b. T H H H H
c. H T H T H
d. Only sequences (a) and (c) are equally likely.
e. All of the above sequences are equally likely.
8. A 95% confidence interval is calculated for the proportion of US households that have a dog, based on a
random sample of US households. The resulting confidence interval is 42% to 48%. This means that
a. 45% of US households have a dog.
b. the probability that the interval includes the population proportion of US households that have a dog is
95%.
c. the probability that the interval includes the sample proportion of US households that have a dog is 95%.
d. if 200 confidence intervals were generated using the same process, about 190 of the confidence intervals
would include the population proportion.
9. To study the effectiveness of a zinc nasal spray for reducing the duration of a common cold, researchers
recruited 104 subjects who agreed to report to their lab within 24 hours of getting cold symptoms.
Each subject was randomly assigned to one of three groups: one received full dosage of the zinc spray,
another received a low dosage, and a third received a placebo spray. The cold symptoms lasted an
average of 1.5 days for the full dosage group, 3.5 days for the low dosage group, and 10 days for the
placebo group. Which of the following is most appropriate for this experiment?
a. The explanatory variable is zinc spray and the response variable is the amount of zinc spray given.
b. The explanatory variable is zinc spray and the response variable is the length of time cold symptoms
lasted.
c. The explanatory variable is the severity of the cold and the response variable is the amount of zinc spray
given.
d. The explanatory variable is the severity of the cold and the response variable is the length of time cold
symptoms lasted.
10. The median salary for Columbus Blue Jackets players for the 2007-2008 season was $1,000,000. The mean
salary for the same season was $1,474,211. Based on the relationship of the mean and the median, we know
that the distribution of salaries for the Columbus Blue Jackets for the 2007-2008 season is most likely
a. right skewed.
b. fairly symmetric.
c. left skewed.
d. Cannot be determined from the information given.
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11. According to the National Association of Home Builders, the median selling price of homes in the United
States is $200,000. Which of the following is the most plausible value for the standard deviation?
a. $20,000
b. $1,000
c. $60,000
d. $200,000
12. In a small city, approximately 15% of those eligible are called for jury duty in any one calendar year. Assume
that jury selection in any year is independent of jury selection in any consecutive year. What is the probability
that a randomly selected person is called for jury duty in exactly one of the next two calendar years?
a. 0.0225
b. 0.1275
c. 0.2550
d. 0.7225
Use the following information for Questions 13-16:
A magazine that publishes product reviews conducted a survey of teenagers’ preferences for cell phones. Three
brands of cell phone designed specifically with teens in mind were the focus of the study. The table summarizes
responses by brand and sex.
Cell Phone
Male
Female
Total
LG Rumor
55
87
142
Sidekick LX
99
150
249
BlackJack II
196
113
309
Total
350
350
700
13. Approximately what percent of teenagers preferred the BlackJack II?
a. 28%
b. 44%
c. 56%
d. 63%
e. 66%
14. What percent of teenagers who preferred the BlackJack II were males?
a. 28%
b. 44%
c. 56%
d. 63%
e. 66%
15. What percent of teenagers preferred the BlackJack II or were males?
a. 28%
b. 44%
c. 56%
d. 63%
e. 66%
Document Summary
Note: this review is longer than a final exam would be, but the questions are representative of the types of questions you could see. There are no guarantees that the final exam looks like the final exam review. It also reports a correlation of -0. 8 between math achievement and a math anxiety test for the same group of students. Only students with scores on all three measures were included in the study. The mean and standard deviation were computed; the standard deviation was 0. The scatterplot tells us, however, that when x is below its mean, y tends to be above its mean, and when x is above its mean, y tends to be below its mean. What is the sign on the correlation coefficient in this case: positive, negative, zero, no way to tell. The resulting confidence interval is 42% to 48%.
