Question

Agri-Beef Inc. operates cattle feed lots in several mid-western states.
The company wishes to estimate the average daily weight gain
of cattle on their lots. To do this a simple random sample
of cattle is taken and the daily weight gain is recorded.
The data below, in pounds, represent the results of the sample.
If you need to download your data set again, you can do so by clicking here.
Hint: Keep in mind that these are small sample confidence intervals.
a.    Construct a 95% confidence interval estimate for the true daily weight gain.
b.    Construct a 99% confidence interval estimate for the true daily weight gain.
c.    Discuss the differences between the two estimates found in parts a and b
and indicate the advantages and disadvantages of each.

Data Set:

5.7
5.7
6
6.5
6.5
6.7
6.7
6.9
6.9
7.2
7.9
8.3
8.7
9.3
9.4 End of problem 1

A survey of 400 women for the American Orthopedic Foot and Ankle Society revealed that 38% wear flats to work.

a. Use this sample information to develop a 99% confidence interval for the population proportion of women who wear flats to work.

b. Suppose the society wished to estimate the proportion of women who wear athletic shoes to work and the proportion of women who wear flats to work within a margin of error of 0.01 (one percentage point) with 95% confidence. Determine the sample size required.

Two separate problems. How would I construct these in excel 2016?

Answer 1

Step 1: Type your data into a single column in Excel.

Step 2: Click the “Data” tab, then click “Data Analysis,” then click “Descriptive Statistics” and “OK.” If you don’t see Data Analysis, load the Excel data analysis toolpak.

Step 3: Enter your input range into the Input Range box.(Select the whole data)

Step 5: Click the “Summary Statistics” check box and then place your chosen confidence level into the ‘Confidence Level for Mean’ check box. For this example, type “95”.

Step 5: Click “OK.”Microsoft Excel will return the confidence interval for the mean and the margin of error for your data.

Now you are ready to calculate the lower limit and the upper limit of the c.i

lower limit=mean-confidence level

upper limit =mean+confidence level.

For 99% confidence interval procedure is the same just change the confidence level to 99%

Here are the steps in picture

Entering the data and selecting the steps

and this is what you get

And for 99% just do this