A manufacturer of candy must monitor the temperature

A manufacturer of candy must monitor the temperature. At which the candies are baked. Too much variation will cause inconsistency in the taste of candy. Past records show that the standard deviation of the temperature has been 1.2 degrees Fahrenheit. A random sample of 30 batches of candy is selected and the sample standard deviation of the temperature is 2.1 degrees Fahrenheit. At the 0.05 level of significance, is there evidence that the population standard deviation has increased above 1.2 degrees Fahrenheit.

A. Hypothesis

B. Test statistics

C. Find p-value

D. Result

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Do people walk faster in the airport when they are departing or when they are arriving? A researcher measured the walking speed of travelers at the different airports in USA. His findings are summarized in the table. Use a 5% level of significance.

Direction of travelers

Mean speed – departure – 260

Mean speed – arrival – 289

Standard deviation – departure – 53

Standard deviation – arrival – 34

Sample size – departure – 25

Sample size – arrival 25

A. Hypothesis

B. Test statistics

C. Find p-value

D. Construct a 95% confidence interval

E. Result