A random sample of 40 college students has a mean earnings of $3120 over the summer months. Assume the population standard deviation of earnings over the summer months for college students is $677 and that the distribution of earnings over the summer months for college students is normally distributed. Determine whether a normal distribution or a t-distribution should be used or whether neither of these can be used to construct a confidence interval.

A normal distribution or z-test is used to construct a confidence interval.

Step-by-step explanation:

We are given the following in the question:

Sample mean, = $3120

Sample size, n = 40

Population standard deviation, σ = $677

The distribution of earnings of college is a normal distribution.

Conditions:

Conclusion:

Thus, we use a normal distribution or z-test to construct a confidence interval.

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note: the best i know.

on monday rodney ate 1/4th of the sandwich = 3/12

on tuesday he ate 1/3rd of the sandwich = 4/12

therefore in total he has eaten = 3/12 + 4/12 = 7/12

thus we can say that he has eaten 7/12 of the sandwich on monday and tuesday alltogether.

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