Hi all, Just attempted this quetsion and unfortunately tripped up on the critical value. I have thought that the population variance is unknown (since not specificied0 so we would use the t distribtuion, but the solutions have used the normal cvs. Is this because n is large so we approximate it to be normal? or was the population variance known the whole time? Thanks Molly
Hi Molly The question mentions the normal distribution and with a sample size of 49 so I would use normal critical values, I would class this as large. The assumption was there that the population variance was known. I would hope they would mention with an unknown variance if they specifically wanted you to use the t-distribution and find values at t_48. Thanks Andrea
