Question

A sample of 1200 computer chips revealed that 72% of the chips fail in the first 1000 hours of their use. The company's promotional literature claimed that below 75% fail in the first 1000 hours of their use. Is there sufficient evidence at the 0.02 level to support the company's claim? State the null and alternative hypotheses for the above scenario.

Answer 1

given data are:-

sample size(n) = 1200

sample proportion () = 72% = 0.72

level of significance () = 0.02

here we will do 1 proportion z test.

hypothesis:-

the alternative hypothesis is the company's claim.

test statistic be:-

z critical value for 98% confidence level left tailed test be:-

[ using z table]

rejection region:-

reject the null hypothesis if,

decision:-

so, we reject the null hypothesis.

conclusion:-

there is sufficient evidence at the 0.02 level to support the company's claim, that below 75% fail in the first 1000 hours of their use.

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