Solve please minimal explanation required

Question 41

The mean number of travel days per year for salespeople employed by three hardware distributors needs to be estimated with a 0.90 degree of confidence. For a small pilot study, the mean was 150 days and the standard deviation was 14 days. If the population mean is estimated within two days, how many salespeople should be sampled?

133

452

511

2,100

Question 42

The mean annual income of certified welders is normally distributed with a mean of $50,000 and a population standard deviation of $2,000. The ship building association wishes to find out whether their welders earn more or less than $50,000 annually. The alternate hypothesis is that the mean is not $50,000. If the level of significance is 0.10, what is the decision rule?

Do not reject the null hypothesis if computedzlies between -1.645 and +1.645; otherwise, reject it.

Do not reject the null hypothesis if computedzis greater than 1.645; otherwise, reject it.

Do not reject the null hypothesis if computedzlies between -1.960 and +1.960; otherwise, reject it.

Reject the null hypothesis if computedzis below -1.960; otherwise, reject it.

Question 43

A student wanted to construct a 95% confidence interval for the mean age of students in her statistics class. She randomly selected nine students. Their mean age was 19.1 years, with a sample standard deviation of 1.5 years. What is the 95% confidence interval for the population mean?

[0.97, 3.27]

[15.64, 22.56]

[17.97, 20.23]

[17.95, 20.25]

Question 44

A local company wants to evaluate their quality of service by surveying their customers. Their budget limits the number of surveys to 100. What is their maximum error of the estimated mean quality for a 95% level of confidence and an estimated standard deviation of 5?

0.9604

0.98

1.96

5%

Question 45

A null hypothesis makes a claim about a __________.

Population parameter

Sample statistic

Sample mean

Type II error

Question 46

When we use a confidence interval to reach a conclusion about the population mean, we are applying a type of reasoning or logic called __________.

Descriptive statistics

The normal distribution

Statistical inference

Graphics

Question 47

The average cost of tuition and room and board at small private liberal arts colleges is reported to be $8,500 per term, but a financial administrator believes that the average cost is higher. A study conducted using 350 small liberal arts colleges showed that the average cost per term is $8,745. The population standard deviation is $1,200. Let = 0.05. Based on the computed test statistic orp-value, what is our decision about the average cost?

Equal to $8,500

Greater than $8,500

Less than $8,500

Not equal to $8,500

Question 49

A random sample of 20 items is selected from a population. When computing a confidence interval for the population mean, what number of degrees of freedom should be used to determine the appropriatet-value?

20

19

21

25

Question 50

If the alternate hypothesis states that 4,000, where is the rejection region for the hypothesis test?

In both tails

In the lower or left tail

In the upper or right tail

In the center