In: Statistics and Probability
The manufacturer of the ColorSmart-5000 television set claims 95
percent of its sets last at least five years without needing a
single repair. In order to test this claim, a consumer group
randomly selects 400 consumers who have owned a ColorSmart-5000
television set for five years. Of these 400 consumers, 316 say
their ColorSmart-5000 television sets did not need a repair,
whereas 84 say their ColorSmart-5000 television sets did need at
least one repair.
(a) Find a 99 percent confidence interval for the proportion of all ColorSmart-5000 television sets that have lasted at least five years without needing a single repair. (Round your answers to 3 decimal places.)
The 99 percent confidence interval is [, ].
(b) Does this confidence interval provide
strong evidence that the percentage of all ColorSmart- 5000
television sets that last at least five years without a single
repair is less than the 95 percent claimed by the
manufacturer?
(Click to select)NoYes , the interval is (Click to select)belowabove .95.