A superintendent of schools wonders if scores on a test of science achievement differ for female and male 8th grade students. To
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Answer:
The 95% confidence interval for the population mean amount spent on groceries by Connecticut families is ($73.20, $280.21).
Step-by-step explanation:
The data for the amount of money spent weekly on groceries is as follows:
S = {210, 23, 350, 112, 27, 175, 275, 50, 95, 450}
<em>n</em> = 10
Compute the sample mean and sample standard deviation:
It is assumed that the data come from a normal distribution.
Since the population standard deviation is not known, use a <em>t</em> confidence interval.
The critical value of <em>t</em> for 95% confidence level and degrees of freedom = n - 1 = 10 - 1 = 9 is:
*Use a <em>t</em>-table.
Compute the 95% confidence interval for the population mean amount spent on groceries by Connecticut families as follows:
Thus, the 95% confidence interval for the population mean amount spent on groceries by Connecticut families is ($73.20, $280.21).