The value of 4 is 4,000 (four thousand)
Answer:
a. t*
b. (22.87, 24.53)
c. yes
Step-by-step explanation:
We have the following data:
mean = m = 23.7
standard deviation = sd = 2.15
x = 20
Thus:
a. The critical value would be t * since the value is m <30
b. whenever the mean is less than 30, the t distribution is used, for 95% confidence interval with degree of freedom = (x - 1) df
= 20 - 1
= 19
now, for this value we look in the table of t, we find that t * = 1.729
m + - t * (sd / x ^ 81/2))
replacing
23.7 + - 1.729 * (2.15 / 20 ^ (1/2))
23.7 + - 0.8312
then the inverval would be:
23.7 + 0.8312 = 24.5312
23.7 - 0.8312 = 22.8688
(22.87, 24.53)
c. yes, the interval is accurate since the mean of 23.7 is within this value
