Question

The COVID-19 pandemic is sending users to Facebook Inc.’s social-networking, messaging and live-streaming platforms in record numbers. A survey recently reports that the mean time people spend on Facebook is 7 hours with a standard deviation of 30 minutes. You randomly select 35 people. What is the probability that their mean time spent on Facebook is less than 6.8 hours?

Answer 1

this is the left tailed test .  

The null and alternative hypothesis is ,

H₀ :   = 6.8

H_a : < 6.8

Test statistic = z

= ( - ) / / n

= (7-6.8) / 30/ 35

z= 0.04