Question

1. A researcher is testing the claim that adults consume an average of at least 1.85 cups of coffee per day. A sample of 35 adults shows a sample mean of 1.70 cups per day with a sample standard deviation of 0.4 cups per day. Test the claim at a 5% level of significance. What is your conclusion?

Answer 1

reject H0

Explanation:

Given that a researcher is testing the claim that adults consume an average of at least 1.85 cups of coffee per day.

A sample of 35 adults shows a sample mean of 1.70 cups per day with a sample standard deviation of 0.4 cups per day.

`H_0:\bar x =1.85\\H_a: \bar x \geq 1.85`

(right tailed test at 5% level of significance)

`\bar x = 1.70\\s = 0.4\\Se = (0.4)/(√(35) ) \\=0.0676`

Test statistic t = mean difference/std error =
`(1.70-1.85)/(0.0676) \\=-2.22`

df = 34

t critical = -1.697

Since our test statistic < t critical we reject null hypothesis..