# probability math homework help

1. For each the following variables from the Salary Data Set provide the measures of location and measures of dispersion for the following variables:

Beginning Salary

Answer:

.

Explanation (include any calculations or software output):

Previous Experience

Answer:

.

Explanation (include any calculations or software output):

Which variable has the greatest relative variability?

Answer:

Explanation (include any calculations or software output):

2. You are the manager of a high-end ladies fashion store. For the past few months you have been gathering data and found that 55% of persons entering the store actually make a purchase. Assume these data follow a Binomial Distribution and use Excel to calculate the following binomial probabilities:

If 15 people enter the store, what is the probability that exactly 8 of them will make a purchase?

Answer:

.

Explanation (include any calculations or software output):

What is the probability that more than 8 of the 15 people will make a purchase?

Answer:

.

Explanation (include any calculations or software output):

3. Using the Salary Data Set what is the probability of randomly selecting one individual (male or female) with a current annual salary of over $40,000?

Answer:

Explanation (include any calculations or software output):

4. The time required to complete a project is normally distributed with a mean of 77 weeks and a standard deviation of 4 weeks. The construction company must pay a penalty if the project is not finished by the due date of the contract. If a construction company bidding on this contract wishes to be 95 percent sure of finishing by the due date, use the NORMINV Excel Function to determine what due date (project week #) should be negotiated?

Answer:

.

Explanation (include any calculations or software output):

5. In a state lottery participants select 8 numbers between 1 and 49. At the end of the week, the state lottery commission randomly draws 8 numbers between 1 and 49. How many different possible winning number combinations could be drawn by the lottery commission?

Answer:

.

Explanation (include any calculations or software output):

6. From the Salary Data Set and assuming that the salary data is a random sample from the population of salaries from the multi-national company use the 95% confidence level in PHStat to estimate the mean beginning salary for company executives.

The 95% confidence level interval is:

Answer:

Explanation (include any calculations or software output):

If you were to change the confidence level to 99%, what would happen to the confidence interval? What is the 99% confidence interval?

Answer:

.

Explanation (include any calculations or software output):

7. Using the Salary Data Set,

1. Create a scatter plot to show this relationship between education and current salary

2. Determine the correlation coefficient between the variables. What does this tell us about the relationship?

Answer:

.

Explanation (include any calculations or software output):

8. Explain why rejecting the null hypothesis does not make the alternative hypothesis true.

Answer in your words:

9. What is the purpose of statistical inference?

Answer in your words:

10. What is the difference between sampling error and the standard error of the mean?

Answer in your words:

11. You are a consultant working for Kaplan Consulting. The Director of Human Resources for a multi-national company has requested help in investigating a pay discrimination complaint brought by a female executive. The company provided the data in the Salary Data Set. Use PHStat and the appropriate t test, to investigate the claim of pay discrimination in the Beginning Salary.

â€œIs there a significant difference between the average female and average male salaries?â€

What is the Null and the Alternative Hypotheses?

Ho:

Ha:

What is your level of alpha (Î±)?

Answer:

Why did you choose this level? Please explain in terms of Type I or Type II errors.

What is the output from your analysis?

Software output or calculations:

What is your decision about the hypothesis based on the software output?

Answer in your words:

Is there a significant difference between the average female and average male salaries? Please write a written statement to the director of Human Resources as to whether they should be concerned about the complaint