Smith_Comp

1. A particular country has 60 total states. If the areas of 55 states are added and the sum is divided by 55, the result is 204,440 square kilometers. Deter whether this result is a statistic or parameter.

A. The result is a statistic because it describes some characteristic of a population.

B. The result is a parameter because it describes some of a sample.

C. The result is a parameter because it describes some characteristic of a population.

D. The result is a statistic because it describes some characteristic of a sample.

2. Determine whether the description corresponds to an observational study or an experiment. Fifty patients on dialysis are divided into two groups. One group receives an experimental drug to fight cancer, the other a placebo. After two years, kidney functionally is measured. Does the description correspond to an observational study or an experiment?

A. Observational study

B. Experiment

3. A packager wraps one item every 5 minutes, so 96 items are completed in his first day of the work. His manager checks his work by randomly selecting an hour of the day, then reviewing all the items he completed that hour.

Does this sampling plan result in a random sample?

Simple random sample?

Does this sampling plan result in a random sample?

A. Yes, because all possible groups of n items have an equal chance of being selected.

B. No, because all possible groups of n items do not have an equal chance of being selected.

C. Yes, because each item has an equal chance of being selected.

D. No, because each item does not have an equal chance of being selected.

Does this sampling plan result in a simple random sample?

A. Yes, because each item has an equal chance of being selected.

B. No, because all possible groups of n items do not have an equal chance of being selected.

C. Yes, because all possible groups of n items have an equal chance of being selected.

D. No, because each item does not have an equal chance of selected.

4. Listed below are the top 10 annual salaries (in millions of dollars) of TV personalities. Find the (a) mean, (b) median, (c) mode, and (d) midrange for the given sample data in millions of dollars.

Given that these are the top 10 salaries, do we know anything about the salaries of TV personalities in general?

Are such top lists valuable for gaining insight into the larger population?

37.2 36.5 34.9 26.9 15.8 12.5 11.9 10.9 8.7 8.6

a. The mean is …… (Type an integer or decimal)

b. The median is….. (Type an integer or decimal)

c. Select the correct choice below and fill in any answer boxes in your choice.

A. The mode is … (Use comma to separate answers as needed)

B. There is no mode.

d. The midrange is….. (Type an integer or a decimal)

Given that these are the top 10 salaries, do we know anything about the salaries of TV personalities in general?

A. Since the mean, median, and midrange are relatively reliable even with small samples, a lot of information is given on the salaries of TV personalities in general.

B. Since the mean, median, and midrange are based on a small sample, no information is given on the salaries of TV personalities in general.

C. Since the sample values are the 10 highest, they give almost no information about the salaries of TV personalities in general.

D. Since the sample values give information about one segment of the salaries of TV personalities, they give a lot of information about the salaries of TV personalities in general.

Are such top 10 lists valuable for gaining insight into the larger population?

A. No, because the mean, median, and midrange are based on a small sample.

B. No, because such top lists represent an extreme subset of the population rather than the larger population.

C. Yes, because such top lists give partial information about the population.

D. Yes, because the mean, median, and midrange are relatively reliable even with small samples.

(Show work for #4)

5. A woman wrote to a newspaper advice columnist and claimed that she gave birth 304 days after a visit from her husband, who was in the navy. Lengths of pregnancies have a mean of 268.2 days and a standard deviation of 15.3 days. Find the z sore for 304 days. Is such a length unusual?

The z score is ….. (Round to two decimal places as needed)

Is a pregnancy length of 304 days unusual?

A. No, because its corresponding z score is less than 2.

B. No, because its corresponding z score is greater than 2.

C. Yes, because its corresponding z score is greater than 2.

D. Yes, because its corresponding z score is less than 2.

(Show work for #5)

6. A brand name has 40 % recognition rate. If the owner of the brand wants to verify that rate by beginning with a small sample of 5 randomly selected consumers, find the probability that exactly 2 of the 5 consumers recognize the brand name. Also, find the probability that the number who recognizes the brand name is not 2.

The probability that exactly 2 of the 5 consumers recognize the brand name is….. (Round to three decimal places as needed)

The probability that the number who recognizes the brand name is not 2 is …..(Round to three decimal places as needed)

(Show work for #6)

7. Women’s heights are normally distributed with mean 63.3 in and standard deviation of 2.5 in. A Social organization for tall people has a requirement that women must be at least 69 in tall. What percentage of women meets that requirement?

The percentage of women that are taller than 69in is …. % (Round to two decimal places as needed)

(Show work for #7)

8. (a) With n=14 and p=0.3, find the binomial probability P(6) by using a binomial probability table. (b) If np ≥ 5 and nq ≥ 5, also estimate the indicated probability by using the normal distribution as an approximation to the binomial; If np < 5 or nq < 5, then state that the normal approximation cannot be used.

(a) Find the probability by using a binomial probability table.

P(6)=…. (Round to three decimal places as needed)

(b) Select the correct choice below and, if necessary, fill in the answer box to complete your choice.

A. P(6)= … (Round to four decimal places as needed)

B. The normal distribution cannot be used.

(Show work for #8)

9. Using the simple random sample of weights of women from a data set, we obtain these sample statistics: n=40 and ẋ145.06 lb. Research from other sources suggests that the population of weights of women has a standard deviation given by σ=30.86lb.

a. Find the best point estimate of the mean weight if all women

b. Find a 95% confidence interval estimate of the mean weight of all women.

a. The best point estimate is ….. lb. (Type an integer or a decimal)

b. The 95 % confidence interval estimate is …. lb < µ <….lb(Round to two decimal places as needed)

10. Find the critical z values. Assume that the normal distribution applies. Two- tailed test; a = 0.06

Z= ….. (Round to two decimal places as needed. Use a comma to separate answers as needed)

11. Identify the type I error and the type II error that correspond to the given hypothesis. The percentage of households with Internet access is less than 60%.

Identify the type I error.

Choose the correct answer below.

A. Fail to reject the null hypothesis that the percentage of households with Internet access is equal to 60% when that percentage is actually less than 60%.

B. Reject the null hypothesis that the percentage of households with Internet access is equal to 60% when that percentage is actually equal to 60%.

C. Reject the null hypothesis that the percentage of households with Internet access is less than 60% when the percentage is actually less than 60%

D. Fail to reject the null hypothesis that the percentage of households with Internet access is less than 60% when the percentage is actually equal to 60%.

Identify the type II error. Choose the correct answer below.

A. Reject the null hypothesis that the percentage of households with Internet access is less than 60% when that percentage is actually less than 60%

B. Fail to reject the null hypothesis that the percentage of households with Internet access is equal to 60% when that percentage is actually less than 60%

C. Fail to reject the null hypothesis that the percentage of households with internet access is less than 60% when the percentage is actually equal to 60%

D. Reject the null hypothesis that the percentage of household with Internet access is equal to 60% when the percentage is actually equal to 60%

12. A sample of 40 women is obtained, and their heights (in inches) and plus rates (in beats per minute) are measured. The linear correlation coefficient is 0.264 and the equation of the regression line is ^y = 18.5 +0.88x where x represents height. The mean of the 40 heights is 63.2 in and the mean of the 40 pulse rates is 73.7 beats per minute. Find the best predicated pulse rate of a woman who is 73 in tall. Use a significance level of α=0.05/

The best predicted pulse rate of a woman who is 73 in tall is ….. beats per minute (Type an integer or decimal rounded to two decimal places as needed)

13. The heights were measured for nine supermodels. They have a mean of 65.5 in. and a standard deviation of 0.6 in. Use the traditional method and a 0.01 significance level to test the claim that supermodels have heights with a mean that is greater than the mean of 63.6 in. for women from the general population.

Choose the correct answer below.

A. Do not reject H₀ since the test statistic 9.500 is greater than the critical value 2.896

B. Reject H₀ since the test statistic 9.500 is greater than the critical value 2.896

C. Reject H₀ since the test statistic 0.105 is not greater than the critical value 2.896

D. Do not reject H₀ since the test statistic 0.105 is not greater than the critical value 2.896

(Show work for #13)

14. A clinical trial tests a methods designed to increase the probability of conceiving a girl. In the study, 403 babies were born, and 213 of them were girls. Use the sample data with a 0.01 significance level to test the claim that with this method, the probability of a being a girl is greater than 0.5. Use this information to answer the following questions.

a. What is the test statistic? z=…… (Round to two decimal places as needed)

b. What is the P-value? P-value= ….. (Round to four decimal places as needed)

c. What is the conclusion?

A. The is not sufficient evidence to support the claim, so the proportion of girls is not significantly different from 0.5

B. There is sufficient evidence to support the claim, so the proportion of girls is significantly different from 0.5

d. Does the method appear to be effective?

A. The study is not able to show that the method is effective in increasing the probability of a baby being a girl.

B. The study is able to show that the method is effective in increasing the probability of a baby being a girl

(Show work for #14)