DATA: 3 1 3 2 5 1 2 1 4 2 1 3 1 1

ka1leE
2020-11-01
Answered

The owner of a large equipment rental company wants to make a rather quick estimate of the average number of days a piece of ditch-digging equipment is rented out per person per time. The company has records of all rentals, but the amount of time required to conduct an audit of all accounts would be prohibitive. The owner decides to take a random sample of rental invoices. Fourteen different rentals of ditch-diggers are selected randomly from the files, yielding the following data. She wants to use these data to construct a $99\mathrm{\%}$ confidence interval to estimate the average number of days that a ditch-digger is rented and assumes that the number of days per rental is normally distributed in the population. Use only the appropriate formula and/or statistical table in your textbook to answer this question. Report your answer to 2 decimal places, using conventional rounding rules.

DATA: 3 1 3 2 5 1 2 1 4 2 1 3 1 1

DATA: 3 1 3 2 5 1 2 1 4 2 1 3 1 1

You can still ask an expert for help

Derrick

Answered 2020-11-02
Author has **94** answers

Step 1

The formula for

Step 2

The sample mean and standard deviation can be obtained using Excel:

Enter the data into Excel file.

Enter

Enter

That is,

Step 3

The degrees of freedom corresponding to t distribution is

From the table of student "t" distribution, the critical value corresponding to 13 degrees of freedom is 3.01.

Step 4

The

asked 2021-08-04

A random sample of 100 automobile owners in the state of Virginia shows that an automobile is driven on average 23,500 kilometers per year with a standard deviation of 3900 kilometers.

Assume the distribution of measurements to be approximately normal.

a) Construct a$99\mathrm{\%}$ confidence interval for the average number of kilometers an automobile is driven annually in Virginia.

b) What can we assert with$99\mathrm{\%}$ confidence about the possible size of our error if we estimate the average number of kilometers driven by car owners in Virginia to be 23,500 kilometers per year?

Assume the distribution of measurements to be approximately normal.

a) Construct a

b) What can we assert with

asked 2021-08-12

In a science fair project, Emily conducted an experiment in which she tested professional touch therapists to see if they could sense her energy field. She flipped a coin to select either her right hand or her left hand, and then she asked the therapists to identify the selected hand by placing their hand just under Emily's hand without seeing it and without touching it. Among 358 trials, the touch therapists were correct 172 times. Complete parts (a) through (d).

a) Given that Emily used a coin toss to select either her right hand or her left hand, what proportion of correct responses would be expected if the touch therapists made random guesses? (Type an integer or a decimal. Do not round.)

b) Using Emily's sample results, what is the best point estimate of the therapists' success rate? (Round to three decimal places as needed.)

c) Using Emily's sample results, construct a

Round to three decimal places as needed - ?

asked 2021-08-09

A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before treatment, 13 subjects had a mean wake time of 101.0 min. After treatment, the 13 subjects had a mean wake time of 94.6 min and a standard deviation of 24.9 min. Assume that the 13 sample values appear to be from a normally distributed population and construct a

Construct the

What does the result suggest about the mean wake time of 101.0 min before the treatment? Does the drug appear to be effective?

The confidence interval ▼ does not include| includes the mean wake time of 101.0 min before the treatment, so the means before and after the treatment ▼ could be the same |are different. This result suggests that the drug treatment ▼ does not have | has a significant effect.

asked 2021-03-09

In a study of the accuracy of fast food drive-through orders, Restaurant A had 298 accurate orders and 51 that were not accurate. a. Construct a 90% confidence interval estimate of the percentage of orders that are not accurate. b. Compare the results from part (a) to this 90% confidence interval for the percentage of orders that are not accurate at Restaurant B:

asked 2021-07-31

Find ${t}_{\frac{\alpha}{2}},\text{}n=20$ for the $95\mathrm{\%}$ confidence interval for the mean.

asked 2021-09-30

A sample selected from a population gave a sample proportion equal to 0.59 .

Round your answers to three decimal places.

a) Make a$95\mathrm{\%}$ confidence interval for p assuming $n=150$

( Enter your answer; confidence interval assuming$n=150$ , lower bound ,Enter your answer; confidence interval assuming $n=150$ , upper bound )

b) Construct a$95\mathrm{\%}$ confidence interval for p assuming $n=600$ . ( Enter your answer; confidence interval assuming $n=600$ , lower bound ,Enter your answer; confidence interval assuming $n=600$ , upper bound )

c) Make a$95\mathrm{\%}$ confidence interval for p assuming $n=1275$ . ( Enter your answer; confidence interval assuming $n=1275$ , lower bound ,Enter your answer; confidence interval assuming $n=1275$ , upper bound )

Round your answers to three decimal places.

a) Make a

( Enter your answer; confidence interval assuming

b) Construct a

c) Make a

asked 2022-04-11

Two-sided confidence intervals and tests

From a sample of 1751 army hospitals, estimate the mean expenses for a full time equivalent employee for all US army hospitals using a$90\mathrm{\%}$ confidence interval given $x=6563$ and $s=2484$ .

From a sample of 1751 army hospitals, estimate the mean expenses for a full time equivalent employee for all US army hospitals using a