Use Sheet 4 of the Excel file to answer the following questions.

A company that makes LED light bulbs claims that the bulbs have a lifetime of 11,000

hours. Quality control tests a random sample of 45

light bulbs to determine if the lifetime is less than 11,000

hours at a confidence level of 0.05

. Create a histogram, and calculate x

, the t

-statistic, and the p

-value.

From the histogram, can normality be assumed? (Yes or No)

(x)=

t =

p =

Since the p-value is (greater or less ) than the significance level of 0.05, the null hypothesis (fails to be rejected or is rejected)

(Sufficient or insufficient) evidence exists that the mean lifetime is less than 11,000 hours.

Numbers from the excel

3.09 2.73 2.58 2.68 2.84 2.68 2.64 2.62 2.35 2.72 2.63 2.77 2.72 3.03 2.71 2.96 2.74 3.01 2.88 2.68 2.83 3.02 2.83 2.71 2.67 2.79 2.65 2.56 2.78 2.89 2.40 2.38 2.41 2.83 2.86 3.01 2.80 2.84 2.95 2.75 2.93 2.48 2.34 2.97 2.85 2.74 2.84 3.10 2.62 2.77