Below is a sample of twenty customers spent for lunch ($) at a fast-food restaurant: 8.20 9.19 6.83 6.50

[answerhappygod]

Below is a sample of twenty customers spent for lunch ($) at a
fast-food restaurant:
8.20
9.19 6.83
6.50 8.34
9.51 7.10
6.80 4.90 7.10
7.89
7.50 5.52
4.90 8.34
9.60 7.10
6.90 7.20
6.80
a. At the 0.05 level of significance, is there evidence that the
mean amount spent for lunch is different from $7.0 (using critical
value approach)?
b. Determine the p-value in (a) and interpret its meaning.
c. What assumption must you make about the population
distribution in order to conduct the t test in (a) and (b)?