1.

Answer to 1:

Confidence interval of mean formula= (Mean +/- Z score * sd/sqrt(n))

Z score at 68% confidence level = 1

Z score at 95% confidence level = 2

Z score at 99.7% confidence level = 3

Given that summary about 2016

Mean = 416.5

Standard deviation = 28.3

n = 19

Now

68% confidence interval for mean

= (Mean +/- Zc * sd/sqrt(n))

= (416.5 +/- 1*28.3/sqrt(19))

= (410.01, 422.99)

Lower value = 410.01

Upper value = 422.99

95% confidence interval for mean

= (Mean +/- Zc * sd/sqrt(n))

= (416.5 +/- 2*28.3/sqrt(19))

= (403.52, 429.48)

Lower value = 403.52

Upper value = 429.48

99.7% confidence interval for mean

(Mean +/- Zc * sd/sqrt(n))

= (416.5 +/- 3*28.3/sqrt(19))

= (397.02, 435.98)

Lower value = 397.02

Upper value = 435.98

Use StatCrunch to determine the frequency AND percentage of observations falling in each ofthese intervals by following the instructions listed below or using another appropriate countingmethod. Properly label and list these counts and percentages in your solutions document.

Go toData Row Selection Interactive Tools. In the Slider selectors box, click thevariable "Final Weight Lift" into the variable box. In the Category selectors box, click thevariable "Year" into the variable box. Click "Compute!" to open the tool.

The box that appears has a slider under the wordsFinal Weight Liftthat allows you to createranges of scores that you determined in number 1. Under Year, select the Year 2016. Use the sliderto obtain the count for each interval from the given above by looking at the "# rows selected" presented inthe first line of the box. (Hint: Click on the square bounds of the interval and use your arrowkeys for more control.) Calculate the percentages from the counts you obtained for eachinterval and include them in your solutions document.