Question

# The average work week for engineers in a start-up company is believed to be about 60...

The average work week for engineers in a start-up company is believed to be about 60 hours. A newly hired engineer hopes that it's shorter. She asks 10 engineering friends in start-ups for the lengths of their average work weeks. Based on the results that follow, should she count on the average work week to be shorter than 60 hours? Conduct a hypothesis test at the 5% level.

Data (length of average work week): 70; 45; 55; 60; 65; 60; 60; 60; 55; 55.

Construct a 95% confidence interval for the true mean. Sketch the graph of the situation. Label the point estimate and the lower and upper bounds of the confidence interval. (Round your lower and upper bounds to two decimal places.)

I already know that the point estimate is 58.50 for sure. I already got that right.

No matter how I calculate it, I cannot get the intervals, I asked a question like this previously here, I got a reply, but the answer was wrong.

I need to know how to do it on a TI 84 plus

We have to find a 95% confidence interval for the true mean by using TI 84 calculator.

First, enter data into the calculator.

Click on STAT ------> Edit -------->Enter values into L1

Then click on STAT -------> TESTS --------->TInterval( ----------> Data --------->

List: L1

Freq: 1

C-Level: 0.95

Calculate

We get a confidence interval (53.716, 63.284)

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If you have any doubt please comment!

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