Question

In: Statistics and Probability

In a survey, 27 people were asked how much they spent on their child's last birthday gift.

In a survey, 27 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $45 and standard deviation of $10. Find the margin of error at a 95% confidence level.

Give your answer to two decimal places.

Expert Solution

Solution:

Given:

X : Amount spent by people on their child's last birthday gift.

Sample Size = n = 27

Sample Mean =

Sample Standard Deviation = $10

We have to find the margin of error at a 95% confidence level.

Formula:

where t_c is t critical value for c = 95% confidence level

Thus two tail area = 1 - c = 1 - 0.95 = 0.05

df = n - 1 = 27 - 1 = 26

Look in t table for df = 26 and two tail area = 0.05 and find t critical value.

t_c = 2.056

Thus

Thus Margin of Error at a 95% confidence level is :

orchestra answered 2 years ago

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