+43 One of your friends is testing the effect of drinking coffee on the duration of cold symptoms. The common cold lasts, on average, 6 days. Your friend starts with no expectations as to whether drinking coffee will have any effect on cold duration. After seeing the results of the experiment, in which the average cold duration was less than 6 days, your friend tests a one-sided alternative about the population mean cold duration when drinking coffee.H0: μcoffee = 6
Ha: μcoffee < 6
She finds z = â1.68 with one-sided P-value P = 0.0465.
Required:
What is the correct two-sided P-value for z = â1.68?
