A group of 10 students who wish to enter a university achieve the following scores: 25,...

A group of 10 students who wish to enter a university achieve the following scores:

25, 17 , 29 , 29, 26, 24 , 23 , 26 , 24 , 33

...Construct a confidence interval for the proportion of students scoring 26 points or less.

...construct a 90% confidence interval for the average score of all students

Solutions

Expert Solution

using excel>Addin>phstat>confidence interval

we have

Confidence Interval Estimate for the Proportion

Data
Sample Size	10
Number of Successes	6
Confidence Level	90%

Intermediate Calculations
Sample Proportion	0.6
Z Value	-1.64485363
Standard Error of the Proportion	0.154919334
Interval Half Width	0.254819628

Confidence Interval
Interval Lower Limit	0.345180372
Interval Upper Limit	0.854819628

a 90 % confidence interval for the proportion of students scoring 26 points or less is ( 0.3452 ,0.8548)

using excel>addin>phstat>confidence interval

we have

Confidence Interval Estimate for the Mean

Data
Sample Standard Deviation	14.37590577
Sample Mean	31
Sample Size	10
Confidence Level	90%

Intermediate Calculations
Standard Error of the Mean	4.546060566
Degrees of Freedom	9
t Value	1.833112933
Interval Half Width	8.333442416

Confidence Interval
Interval Lower Limit	22.67
Interval Upper Limit	39.33

a 90% confidence interval for the average score of all students (22.67,39.33)

orchestra answered 1 year ago

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