Q1.(10 pts) The fridge manufacturer claims the average daily electricity consumption of one energy efficient model...

Q1.(10 pts) The fridge manufacturer claims the average daily electricity consumption of one energy efficient model is 0.5 kW.h, the standard deviation of the daily electricity consumption is 0.16 kW.h. For one random sample of 45 fridges, Find the probability that the sample average daily electricity consumption is greater than 0.55 kW.h.

Q2.(10 pts) Following the above Q1,

1.(5 pts) Given a random sample 45 fridges of this model, the average daily electricity consumption of this sample is 0.52 kW.h, calculate 99% two-sided confidence interval for the true average daily electricity consumption.

2.(5 pts) find the sample size ?n such that the 99% two-sided confidence interval is at most 0.1.

Q3.(10 pts) Following the above Q1, the manufacturer recently improved technique and claims that the average daily electricity consumption decreased after the improvement. The suggested average daily electricity consumption is 0.5 kW.h before the technique improvement. One random sample of 50 fridges is selected after the improvement, the sample mean is 0.49. Implement a hypothesis test for the manufacturer's claim. Set significance level as 0.1.

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(Q1).

(Q2).1.

(Q2).2.

(Q3).

orchestra answered 1 year ago

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