Question

In: Statistics and Probability

Part 1) Suppose Clocks Inc had a random sample of n = 118 measurements is selected...

Part 1) Suppose Clocks Inc had a random sample of n = 118 measurements is selected from a population with mean μ = 25 and standard deviation σ = 9. Find the value of the standard error, σ x ¯ (round to 1 decimal place).

= ?

Part 2) A Clocks Inc made another random sample of 105 students has a test score average of 74 with a standard deviation of 9.3. Find the margin of error if the confidence level is 0.99. (Round answer to two decimal places)

Solutions

Expert Solution

Solution :

Given that,

Part 1)

mean = = 25

standard deviation = = 9

n = 118

The sampling distribution of mean and standard error is ,

= 25

= / n = 9 / 118 = 0.8

Part 2)

t /2,df = 2.624

Margin of error = E = t/2,df * (s /n)

= 2.624 * (9.3 / 105)

Margin of error = E = 2.38


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