"4. a coffee manufacturer is interested in whether the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers. assume the population standard deviation for those drinking regular coffee is 1.20 cups per day and 1.36 cups per day for those drinking decaffeinated coffee. a random sample of 50 regular-coffee drinkers showed a mean of 4.35 cups per day. a sample of 40 decaffeinated-coffee drinkers showed a mean of 5.84 cups per day. use the .01 significance level."(1) this a (one tailed or two-tailed) test? ?

Answer and Step-by-step explanation

Given:

 Sample size = n1 = 50

Sample mean = x1 = 3.84

Population standard deviation= ∂1 = 1.20

Sample size = n2 = 40

Sample mean = x2 = 3.35

Population standard deviation = ∂2 =1.36

Significance level = a = 0.05

Daily consumption of regular-coffee is greater than decaffeinated-coffee.

The hypothesis:

H0 : µ1 ≤ µ2

Ha : µ1 > µ2

If alternative hypothesis Ha contains <, then test is left tailed.

If the alternative hypothesis Ha contains >, then test is right tailed.

If the alternative hypothesis Ha contains ≠, then test is two tailed.

Right tailed test.

P ( z > z0)  = 0.05

Let determine the z score that corresponds with probability of 1 – 0.5 – 0.05 =0.45

Determine the value of test statistic:

Z = x1 – x2 / √(∂1/n1+∂2/n2)

The p value  is the probability of obtaining a value more extreme or equ

is there any photos or whatever?

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step-by-step explanation: