A company wanted to estimate the mean lifetime of its new model of lightbulbs. They use a method for testing bulbs that accelerates the process so the bulbs burn out relatively quickly, and the company can accurately calculate the corresponding lifetime under regular usage. They took a random sample of 555 of these new bulbs and calculated their lifetimes. Here are the data and summary statistics:

Bulb 1 2 3 4 5
Lifetime 14.2 12.2 13.4 12.6 14.6
Mean= 13.4 years
Standard deviation= sx =1.02 years

Required:
Wrtite a 90% confidence interval for the mean lifetime in years) for this type of bulb.

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hyuntra hyuntra · Answer 1 · 2021-04-25T23:29:22+02:00

Answer:

13.4±2.132(1.02/5)

Step-by-step explanation:

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AFOKE88 AFOKE88 · Answer 2 · 2022-03-22T13:32:30+01:00

The confidence interval for the mean life time is; CI = 13.4 ± 3.678(1.02/5)

Formula for confidence interval is;

CI = x' ± z(s/√n)

We are given;

Mean; x' = 13.4

Standard deviation; s = 1.02

Sample size; n = 5

z-score at confidence level of 90% = 1.645

Thus;

CI = 13.4 ± 1.645(1.02/√5)

CI = 13.4 ± 3.678(1.02/5)

Read more about Confidence Interval at; https://brainly.com/question/17097944