The mean data use for smartphone users is claimed to be 1.8 gigabytes per month.

Suppose data use is recorded for 49 randomly selected smartphone users and the average use is found to be 1.86 gigabytes per month.

Assume that the population standard deviation is 0.20 gigabytes per month.

• Test this claim for significance level 5%.
• Retest this claim using the p-value approach