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If you use a normal distribution: You will need to: Click on \'Stat\'. Click on

ID: 3156675 • Letter: I

Question

If you use a normal distribution: You will need to: Click on 'Stat'. Click on 'Z stats', then 'One sample', and then 'with data'. Then click on 'Gas mileages (in miles per gallon)' to select the column. Type in the population standard deviation, if given. Select the 'Confidence Interval' button and make sure the level is set at .95. Then click on 'Compute!'. Click on 'Options', then 'Copy', and paste into your solutions file and make explain your findings as asked below.

If you use a t-distribution:  You will need to: Click on 'Stat'. Click on 'T stats', then 'One sample', and then 'with data'. Click on 'Gas mileages (in miles per gallon)' to select the column. Select the 'Confidence Interval' button and make sure the level is set at .95. Then click on 'Compute!'. Click on Options, then Copy, and follow the directions to copy and paste into your solutions file as directed and make explain your findings as asked below.

1.  You will find the data for #33 loaded in StatCrunch labeled '6.2 Problem 33'. Click on it to bring up the data set for this problem.  Please also refer to Problem #33 in Section 6.2 of your textbook to verify whether or not the population standard deviation is known. Then use the normal distribution or the t-distribution to construct a 95% confidence interval for the population mean. You need to explain which distribution you will use and why (make reference to the table on page 314). Once you have produced the output, click on Options, click on Copy, and follow the directions to copy and paste the output into your solutions file.  Give an interpretation as to what the confidence interval represents.

I am mostly looking for help on the interpretation with this problem!!

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Explanation / Answer

One-Sample Statistics

N

Mean

Std. Deviation

Std. Error Mean

X

45

21.71

3.224

.481

One-Sample Test

Test Value = 0

t

df

Sig. (2-tailed)

Mean Difference

95% Confidence Interval of the Difference

Lower

Upper

gas mileage

45.179

44

.000

21.711

20.74

22.68

Interpretation: here p=0.000<0.01

The mean value was significantly different from ‘0’

One-Sample Statistics

N

Mean

Std. Deviation

Std. Error Mean

X

45

21.71

3.224

.481