1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Black_prince [1.1K]
3 years ago
10

Senior management of a consulting services firm is concerned about a growing decline in the firm’s weekly number of billable hou

rs. The firm expects each professional employee to spend at least 40 hours per week on work. In an effort to understand this problem better, management would like to estimate the standard deviation of the number of hours their employees spend on work-related activities in a typical week. Rather than reviewing the records of all the firm’s full-time employees, the management randomly selected a sample of size 51 from the available frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively. Construct a 99% confidence interval for the standard deviation of the number of hours this firm’s employees spend on work-related activities in a typical week
Mathematics
1 answer:
Reil [10]3 years ago
7 0

Answer:  (45.79, 51.21)

Step-by-step explanation:

Given : Significance level : \alpha: 1-0.99=0.01

Sample size : n= 51 , which is a large sample (n>30), so we use z-test.

Critical value: z_{\alpha/2}=2.576

Sample mean : \overline{x}= 48.5\text{ hours}

Standard deviation : \sigma=7.5\text{ hours}

The confidence interval for population means is given by :-

\overline{x}\pm z_{\alpha/2}\dfrac{\sigma}{\sqrt{n}}

i.e. 48.5\pm(2.576)\dfrac{7.5}{\sqrt{51}}

i.e.48.5\pm2.70534112234\\\\\approx48.5\pm2.71\\\\=(48.5-2.71, 48.5+2.71)=(45.79, 51.21)

Hence, 99% confidence interval for the standard deviation of the number of hours this firm’s employees spend on work-related activities in a typical week =  (45.79, 51.21)

You might be interested in
Suppose you have read two different books on world war 2 and each book has different arguments about how the war started which o
Dafna11 [192]

Answer:

Well this is my opinion I would try to compared both them and see if they have something familiar in their arguments. If not I would try to view their different point of view and write your own opinion about it. I would check out another book about the World War 2 because there's infinite of books about it.

3 0
2 years ago
What is -88 5x=x+62 answer
garik1379 [7]

Answer:

you cant solve that is it -88 * -88 5x=x+625x=x+62

Step-by-step explanation:

8 0
3 years ago
Pizza Perfection sold 93 pizzas on Monday, 67 pizzas on Tuesday, 78 pizzas on Wednesday, 44 pizzas
Nezavi [6.7K]
(93+67+78+44+123)/5=405/5=81 pizzas per day on average

C is your answer.
4 0
3 years ago
Read 2 more answers
Solve please. Just give the answer plz!
Studentka2010 [4]

Answer:

I think the answer is 6 hours. I'm not sure though

5 0
3 years ago
Read 2 more answers
If CM=15, Find DC and DM
Ghella [55]

image ????? please attach image and try again

8 0
3 years ago
Other questions:
  • Given: ∠KJL and ∠KML intercept arc KL. Prove: m∠KJL = m∠KML
    7·2 answers
  • Ind an equation for the nth term of the arithmetic sequence.<br><br> a14 = -33, a15 = 9
    12·1 answer
  • What is the slope intercept of 2y=14-4x
    6·2 answers
  • Line h contains the points (3,0) and (0,4). which point lies on a line that is perpendicular to line h and passes through point
    13·1 answer
  • How to use and example to describe the multiplicative relationship between two equivalent ratios
    8·1 answer
  • Which graph represents the equation y = x2 + 1?
    11·1 answer
  • 5 1/2 by 4 3/4 by 1/4 scale it down by 1/10
    11·1 answer
  • I need help. I’ve been stuck
    12·1 answer
  • Please answer the question correctly with factual information for brainliest.
    12·1 answer
  • The diameter is twice the radius<br> True<br> O False
    8·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!