A random sample of 140 forty-year-old men contains 25 smokers. Find the P-value for a hypothesis test to determine whether the percentage of forty-year-old men that smoke differs from 22.
A) 0.4010 B) 0.3898 C) 0.1949 D) 0.1401
Q. 2The heights of adult women have a bell-shaped distribution. Give an example of a data set whose distribution is likely to be right skewed. Explain why you think the distribution will be skewed to the right.
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Q. 3How does the standard normal distribution differ from a nonstandard normal distribution? Why is it necessary to standardize in order to find percentages for nonstandard normal variables?
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Q. 4Suppose that a data set has a minimum value of 28 and a maximum value of 73 and that you want 5 classes. Explain how to find the class width for this frequency distribution. What happens if you mistakenly use a class width of 9 instead of 10?
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Q. 5A salesman boasts to a farmer that his new fertilizer will increase the yield of the farmer's crops by 15. The farmer wishes to test the effects of the new fertilizer on her corn yield.
She has four equal sized plots of landone with sandy soil, one with rocky soil, one with clay-rich soil, and one with average soil. She divides each of the four plots into three equal sized portions and randomly labels them A, B and C. The four A portions are treated with her old fertilizer. The four B portions are treated with the new fertilizer. The four C portions receive no fertilizer. At harvest time, the corn yield is recorded for each section of land. What is the claim she is testing?
A) The A sections had at least a 15 increase in yield.
B) The new fertilizer yielded at least a 15 improvement.
C) The total yield increased at least 15.
D) The average soil field had at least a 15 increase in yield.
Q. 6Which of the variables below do you think will be roughly normally distributed?
a. Weights of 10 year old boys
b. Incomes of 40 year old adults
c. The numbers that show up when you roll a balanced die
d. The amount of coffee which a filling machine puts into 4 ounce jars
A) a and d B) a only C) a, b, d D) a, b, c, d
Q. 7For a given data set, why might a researcher prefer to study organized data rather than the original data? Can you think of any circumstances in which a researcher may prefer to use the original data rather than organized data?
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