Answer: 0.84134
Step-by-step explanation:
We need to find the z-score for the given information first since this will help us find the probability. The formula for this is
Z score =
We have
66 inches (the raw score)
70 inches (the population mean)
= 4 inches (the standard deviation)
This gives
Z score = =
If you use a calculator, or a Z-score table then P(x > Z) is just P(Z > -1) which gives a probability of 0.84134.
The confidence interval for the mean usage of water is (18.7,20.5).
Given population standard deviation of 2.4, mean of 19.5 gallons per day and confidence interval of 98%.
We have to find the confidence interval for the mean usage of water.
To find out the confidence interval we have to first find margin of error.
μ=19.5
σ=2.4
α=0.98
α/2=0.49
We have to find the z value for the p value 0.49 which is z=2.33
Margin of error=z*μ/
=2.33*19.5/
=0.82
lower level=mean -m
=19.5-0.82
=18.68
after rounding upto 1 decimal
=18.7
upper mean = mean+m
=19.5+0.82
=20.52
Hence the confidence interval for the usage of water is (18.7,20.52).
Learn more about margin of error at brainly.com/question/10218601
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