The Federal Government wants to determine if the mean number of business e-mails sent and received per business day by its employees differs from the mean number of e-mails sent and received per day by corporate employees, which is 101.5. Suppose the department electronically collects information on the number of business e-mails sent and received on a randomly selected business day over the past year from each of 10,163 randomly selected Federal employees. The results are provided in the file FedEmail. Test the Federal Government’s hypothesis at α = 0.01. Discuss the practical significance of the results.
The hypothesis being tested is:
H0: µ = 101.5
Ha: µ ≠ 101.5
The test statistic, z = (x - µ)/σ/√n
z = (100.47 - 101.5)/25/√10163
z = -4.15
The p-value is 0.0000.
Since the p-value (0.0000) is less than the significance level (0.01), we can reject the null hypothesis.
Therefore, we can conclude that the mean number of business e-mails sent and received per business day by its employees differs from the mean number of e-mails sent and received per day by corporate employees, which is 101.5.
Please give me a thumbs-up if this helps you out. Thank you!
The Federal Government wants to determine if the mean number of business e-mails sent and received...
A professional employee in a large corporation receives an average of µ = 41.7 e-mails per day. An anti-spam protection program was installed in the company's server and one month later a random sample of 45 employees showed that they were receiving an average of ?̅= 36.2 e-mails per day. Assume that ơ = 18.45. Use a 5% level of significance to test whether there has been a change (either way) in the average number of emails received per day...
+ 10 The average number of text messages sent and received each day by people of selected ages is shown in the table below. T + Х X1 Vi 20 110 30 42 40 26 50 14 60 10 70 0 5 10 14 3 x Find a cubic polynomial function I) that models these data, where & the age. The basic form would (x1)* + b(x1)2 + cx1 + d for the + 10 + 3 X c Find...
Hypothesis Testing 1. According to the U.S. Postal Service, the mean weight of mail received by Americans in 2017 through the Postal Service was 57.2 pounds. One hundred randomly selected Americans were asked to keep all their mail for last year. It was found that they received an average of 56.1 pounds of mail last year. Suppose that the population standard deviation is 9.2 pounds. Test the claim that the mean weight of mail received by Americans in 2017 through...
the mean number of sick days an employee takes per year is believed to be about 10. Members of a personnel department do not believe this figure. They randomly survey B employees. The number of sick days that the mean number is about 107 Conduct a hypothesis test at the 5% level. they took for the past year are as follows: 12; 6; 14 5 11; 6;10. Lt X the number of sick days they took for the past year....
2. An obstetrician wanted to determine whether the mean number of births was the same for each of the five days of the week. She randomly selected eight days for each of the five weekdays and recorded the number of births on that day in the data table below. Refer to the ANOVA results from Excel. Monday Tuesday Wednesday Thursday Friday 10023 10265 10283 10456 10691 11189 11198 11465 11045 11621 11753 11944 12509 12577 12927 13521 11346 11084 11593...
1. The mean number of days it takes an employer to approve medical leave is believed to be about ten. Members of a collective bargaining unit do not believe this figure. They randomly survey eight employees. The number of days they took to approve medical leave are as follows: 12; 4; 15; 3; 11; 8; 6; 8. Let X = the number of days the employer took to approve medical leave. (a) Identify a null and alternative hypothesis. (b) Determine...
Message Therapy
Does e-mail spam affect everyone at the University of Ottawa
equally? To answer this, a small study was conducted by randomly
selecting 10 each of professors, administrators and students. Each
person was asked to count the number of spam messages received on a
given day. Some of the results are presented below.
a) Fill in the correct values for the missing quantities in the
ANOVA table above. Show your computations reporting a maximum of
two decimal places.
b)...
4.3.5 Refer to Exercise 4.3.4. Find the mean and variance of the number of people tested for HIV in samples of size 15. 4.3.6 Refer to Exercise 4.3.4. Suppose that we were to take a simple random sample of 25 adults today and find that two have been tested for HIV at some point in their life. Would these results be surprising? Why or why not? BINOMIAL TABLES 4.3.7 Coughlin et al. (A-6) estimated the percentage of women living in...
8. The lengths of pregnancies are normally distributed with a mean of 267 days and a standard deviation of 15 days. (a) Find the probability that an individual woman has a pregnancy shorter than 259 days. (b) If 36 women are randomly selected, find the probability that they have a mean preg- nancy shorter than 259 days. (c) There should be a difference in your method for the previous two questions. Explain what you did differently for each problem and...
1. Determine the area under the standard normal curve that lies to the right of z = -.22 z = .29 c = 1.05 and d = -.97 2. A bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. If an applicant is randomly selected, find the probability of a rating that is between 200 and 275. Round your answer to four decimal places. 3. The...