About 70% of Earth’s surface is covered by water. If the diameter of Earth is about 12,750 km, find the area not covered by wate
1 answer:
You might be interested in
Answer: The margin of error = 3.71, confidence interval = (354.04, 361.46) and it means that mean cost is lies within the confidence interval.
Step-by-step explanation:
Since we have given that
Sample size = 400
Mean = $357.75
Standard deviation = $37.89
At 95% confidence level, z = 1.96
We first find the margin of error.
Margin of error is given by
95% confidence interval would be
Hence, the margin of error = 3.71, confidence interval = (354.04, 361.46) and it means that mean cost is lies within the confidence interval.
Let 
be the random variable for the weight of any given can, and let 
and 
be the mean and standard deviation, respectively, for the distribution of .
You have
Recall that for any normal distribution, approximately 99.7% of it lies within three standard deviations of the mean, i.e.
. This means 0.3% must lie outside this range, 
. Because the distribution is symmetric, it follows that 
.
Also recall that for any normal distribution, about 95% of it falls within two standard deviations of the mean, so
, which means 5% falls outside, and by symmetry, 
.
Together this means
Solving for the mean and standard deviation gives
and 
.
You have
Recall that for any normal distribution, approximately 99.7% of it lies within three standard deviations of the mean, i.e.
Also recall that for any normal distribution, about 95% of it falls within two standard deviations of the mean, so
Together this means
Solving for the mean and standard deviation gives