Q: A highly selective boarding school will only admit students who place at least 1.5 z-scores above the mean on a standardized test with mean $$\mu = 110$$ and standard deviation $$\sigma = 12. $$What is the minimum score required?

$$128 ($$calculated as $$110 + 1.5 \times 12)$$

Q: A researcher wants to estimate the proportion of adults with high-speed Internet access. What sample size should be obtained to estimate within $$0.025$$ with $$99\%$$ confidence, using no prior estimate?

$$n = \left(\frac{2.576}{0.025}\$$right)^2$$ \times 0.25$$

Question 1

Which of the following best describes the difference between descriptive statistics and inferential statistics?

Accepted Answer

Descriptive statistics summarize and organize data, while inferential statistics use sample data to make generalizations about a population.

Question 2

A city council wants to survey residents about building a new library. Which sampling method is most appropriate?

Accepted Answer

Survey a random sample of persons within each neighborhood of the town.

Question 3

Which type of bias occurs because we do not obtain complete information about a population?

Accepted Answer

Nonresponse bias

Question 4

Given the Yelp ratings for Hot Doug’s, what percentage of ratings are 5 Star ratings? (Round to the nearest whole percent)

Accepted Answer

70%

Question 5

The graph of company expenditures is misleading because it appears that twice as much money is spent on wages than products. What could be done to improve the graphic?

Accepted Answer

The lengths of the bars should be proportional to the percentages.

Question 6

Scores of an IQ test have a bell-shaped distribution with a mean of 100 and a standard deviation of 12. Use the Empirical Rule to determine the percentage of people with an IQ between 76 and 124.

Accepted Answer

$$95\%$$

Question 7

Daniel’s SAT Mathematics score of 600 is in the 70th percentile. What does this mean?

Accepted Answer

Daniel scored higher than 70% of the test takers.

Question 8

A highly selective boarding school will only admit students who place at least 1.5 z-scores above the mean on a standardized test with mean $$\mu = 110$$ and standard deviation $$\sigma = 12. $$What is the minimum score required?

Accepted Answer

$$128 ($$calculated as $$110 + 1.5 	imes 12)$$

Question 9

Which of the following statements about the correlation coefficient $$r is $$correct?

Accepted Answer

The correlation coefficient $$r$$ must be between $$-1$$ and $$1.$$

Question 10

If a scatterplot shows a negative, moderately strong relationship between X and Y with one outlier, which statement best describes the plot?

Accepted Answer

There is a negative, moderately strong relationship between X and Y with one outlier.

Question 11

If we find a linear correlation between the concentration of carbon dioxide in the atmosphere and global temperature, does this indicate causation?

Accepted Answer

No, correlation does not imply causation.

Question 12

A statistics class surveyed weekly food spending and found a mean of $$31.52$$, median of $$30.00$$, and sample standard deviation of $$9.60. If a $$value entered as $$138$$ should have been $$38$$, which is true after recalculating?

Accepted Answer

The value of the median stays the same, the value of the mean decreases.

Question 13

A probability experiment consists of tossing two fair coins. What is the probability of getting exactly one head?

Accepted Answer

$$\frac{1}{2}$$

Question 14

If the probability of it raining tomorrow is $$0.3$$, what is the probability that it will not rain tomorrow?

Accepted Answer

$$0.7$$

Question 15

According to Verizon, 25% of U.S. households are wireless-only. In a random sample of 300 households, what is the expected number (mean) of wireless-only households?

Accepted Answer

$$75$$

Question 16

Which of the following is NOT a property of the Normal Density Curve?

Accepted Answer

The curve has two peaks.

Question 17

A researcher wants to estimate the proportion of adults with high-speed Internet access. What sample size should be obtained to estimate within $$0.025$$ with $$99\%$$ confidence, using no prior estimate?

Accepted Answer

$$n = \left(\frac{2.576}{0.025}\$$right)^2$$ 	imes 0.25$$

Question 18

In a clinical trial, 50 out of 1655 in the Clarinex group and 31 out of 1652 in the placebo group experienced dry mouth. What is the response variable, and is it qualitative or quantitative?

Accepted Answer

The response variable is experiencing dry mouth, and it is qualitative.

Statistics Final Exam Review – Step-by-Step Guidance

Guida di studio - Domande di pratica

Study guide - Flashcard