Question

The packaging of an electric light bulb states that the average length of life of bulbs is 1000 hours. A consumer association thinks that this is an overestimate and tests a random sample of 64 bulbs, recording the life 𝒙 hours, of each bulb. The results are summarized as follows:

∑ 𝒙 = 𝟔𝟑𝟗𝟏𝟎. 𝟒 and ∑ 𝒙

𝟐 = 𝟔𝟑𝟖𝟐𝟒𝟎𝟔𝟏

Answer 1

mean $\mu_1$ = $\dfrac{\sum x}{n} =\frac{63910.4}{64}=998.6 \ h$

mean $\mu_2$ = $\dfrac{\sum x_2}{n} =\frac{63824.061}{64}=997.25 \ h$