Suppose it is believed that college students spend 41 minutes a day on YouTube. Assume the distribution is known to be approximately normal distribution. You believe that the mean time is less than 41 minutes.

You take a sample of 8 college students.

DATA

X	f
19	1
24	1
28	2
39	2
41	1
46	1

What is the observed sample mean?

What is the estimated standard deviation of the population?

Assuming the null is true, what is the mean of the sampling distribution?

What is the median?

What is the sum of squares deviation?

What is the obtained t?

What can you conclude?

Assuming the null is true, on average, how far would we expect our sample mean to be from the null?

What is the shape of the sample distribution?

Based on the sample mean, what is the 90% confidence interval?