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Please answer with explanation ASAP!

Step-by-step explanation:

the first one

1) The mean calculated for this case is

2)  

3)

4) B. An interval estimate gives us a sense of the accuracy of the point estimate whereas a point estimate alone does not.

Because with the confidence interval we know the confidence level of the interval, and the limits for the parameter at some significance level.  

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Part 1

In order to calculate the mean and the sample deviation we can use the following formulas:  

(a)  

(b)  

The mean calculated for this case is

The sample deviation calculated

population mean (variable of interest)

n=6 represent the sample size  

Part 2

The confidence interval for the mean is given by the following formula:

  (1)

So if we have the margin of error 5.4mm we can find the lowr limit like this:

Part 3

Part 4

B. An interval estimate gives us a sense of the accuracy of the point estimate whereas a point estimate alone does not.

Because with the confidence interval we know the confidence level of the interval, and the limits for the parameter at some significance level.