1. (18.29) An anthropologist claims that color blindness is less common in socie
ID: 3224358 • Letter: 1
Question
1.
(18.29) An anthropologist claims that color blindness is less common in societies that live by hunting and gathering than in settled agricultural societies.
He tests a number of adults in two populations in Africa, one of each type.
The proportion of color-blind people is significantly lower (P < 0.05) in the hunter-gatherer population.
What additional information would you want to help you decide whether you believe the anthropologist's claim?
Whether the two populations have similar spreads.
2.
(18.30) A market researcher chooses at random from women entering a large outlet mall. One outcome of the study is a 95% confidence interval for the mean of the highest price you would pay for a pair of shoes.
Step 1:
Explain why this confidence interval does not give useful information about the population of all women.
Because the required sample, as stated, is a convenience sample, and so is the chosen sample.
(18.31) The 2013 Youth Risk Behavior Survey found that 326 individuals in its random sample of 1216 Ohio high school students said that they had had multiple sexual partners during their life. That’s 27% of the sample.
Step 1:
Why is this estimate likely to be biased?
Because people might fear to admit that they cheat on their partners.
Because only 1216 students participated in this survey.
Because this estimate is based on the answers of only 27% of the sample.
Because people might be ashamed to admit that they change partners very often, as this behavior may be considered immoral by some.
Enter the number(s) of the choice(s) you wish to select. Separate multiple selections with commas or semicolons. Your selections:
Yes.
Because as there are more individuals in the sample, each of them has a larger effect on the mean, which is the center of the confidence interval
.6.
Data Set
1.
(18.29) An anthropologist claims that color blindness is less common in societies that live by hunting and gathering than in settled agricultural societies.
He tests a number of adults in two populations in Africa, one of each type.
The proportion of color-blind people is significantly lower (P < 0.05) in the hunter-gatherer population.
What additional information would you want to help you decide whether you believe the anthropologist's claim?
Whether the two populations have similar spreads.
2.
(18.30) A market researcher chooses at random from women entering a large outlet mall. One outcome of the study is a 95% confidence interval for the mean of the highest price you would pay for a pair of shoes.
Step 1:
Explain why this confidence interval does not give useful information about the population of all women.
Step 2:
Explain why this confidence interval may give useful information about the population of women who visit that large outlet mall. Because the sample is random, the sample is likely to represent the population of all women who shop at outlet malls. Because there are not too many women in one mall, even though it is large, hence it is possible to ask all the women in the mall, and obtain an accurate answer. Because the mall is an SRS of all large outlet malls.
Because the required sample, as stated, is a convenience sample, and so is the chosen sample.
(18.31) The 2013 Youth Risk Behavior Survey found that 326 individuals in its random sample of 1216 Ohio high school students said that they had had multiple sexual partners during their life. That’s 27% of the sample.
Step 1:
Why is this estimate likely to be biased?
Because people might fear to admit that they cheat on their partners.
Because only 1216 students participated in this survey.
Because this estimate is based on the answers of only 27% of the sample.
Because people might be ashamed to admit that they change partners very often, as this behavior may be considered immoral by some.
Enter the number(s) of the choice(s) you wish to select. Separate multiple selections with commas or semicolons. Your selections:
Step 2:Does the margin of error of a 95% confidence interval for the proportion of all Ohio high school students with multiple partners during their life allow for this bias? No.
Yes.
5. (18.33) Examining data on how long students take to complete their degree program, you find one outlier.Step 1:
Will this outlier have a greater effect on a confidence interval for mean completion time if your sample is small or large? small large Step 2:
Why? Explain your answer to the previous question. Because as there are more individuals in the sample, each of them has a larger effect on the standard deviation, which is the center of the confidence interval. Because as there are more individuals in the sample, each of them has a smaller effect on the standard deviation, which is the center of the confidence interval. Because as there are more individuals in the sample, each of them has a smaller effect on the mean, which is the center of the confidence interval.
Because as there are more individuals in the sample, each of them has a larger effect on the mean, which is the center of the confidence interval
.6.
(18.34) Here are data on the percent change in the total mass (in tons) of wildlife in several West African game preserves in the years 1971 to 1999:
Data Set
Software gives the 95% confidence interval for the mean annual percent change as 6.66% to 2.55%.There are several reasons why we might not trust this interval.
Step 1:
Examine the distribution of the data.
What feature of the distribution throws doubt on the validity of statistical inference? The distribution has an outlier. There is a lot of variability in the data. The sample is too small. The distribution is skewed.
Step 2:
Plot the percents against year.
What trend do you see in this time series? The timeplot shows an increasing trend over time. The timeplot shows no clear trend over time. There is a lot of variability about a certain horizontal line. The timeplot shows a decreasing trend over time.
Step 3:
Explain why a trend over time casts doubt on the condition that years 1971 to 1999 can be treated as an SRS from a larger population of years. When the data shows a trend over time, the sample cannot be treated as if it comes from a single population. Because a trend shows that the population is extremely non-Normal. Since that sample is taken from consecutive years, it may not be considered as an SRS from the population. Because a trend indicates on extreme observations which are not likely to occur if the sample was an SRS. eBook
Explanation / Answer
#1
Whether the chosen adults are SRS's from the two populations.
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#2
Step 1: Because a convenience sample was used.
Step 2: Because the sample is random, the sample is likely to represent the population of all women who shop at outlet malls.