The overhead reach distances of adult females are normally distributed with a mean of

200 cm and a standard deviation of

8 cm.
a. find the probability that an individual distance is greater than
210.00
210.00 cm.
b. find the probability that the mean for
25
randomly selected distances is greater than
198.70 cm.

c. why can the normal distribution be used in part (b), even though the sample size does not exceed 30?

a)

The probability that an individual distance is greater than  210.00 cm is 0.1056

b)

The probability that the mean for  25  randomly selected distances is greater than  198.70 cm is 0.7917

c)

The normal distribution be used in part (b), even though the sample size does not exceed 30 since the parent population from which the sample has be obtained is Normal.

Step-by-step explanation:

a)

We let the random variable X denote the overhead reach distances of individual adult females. This implies that X is normally distributed with a mean of 200 cm and a standard deviation of 8 cm.

The probability that an individual distance is greater than 210 can be written as;

Pr(X>210)

We standardize the value to obtain the associated z-score;

Using the standard normal tables, the area to the right of 1.25 is 0.1056. Therefore, the probability that an individual distance is greater than  

210.00 cm is 0.1056.

b)

The first step will be to determine the sampling distribution of the sample mean given that the variable overhead reach distance is normally distributed with a mean of  200 cm and a standard deviation of  8 cm.

In this case, the sample mean will also be normally distributed with a mean of 200 cm and a standard deviation of;

The probability that the mean for  25  randomly selected distances is greater than  198.70 cm;

Pr(sample mean >198.70)

We standardize the value to obtain the associated z-score;

Using the standard normal tables, the area to the right of -0.8125 is 0.7917. Therefore, the probability that the mean for  25  randomly selected distances is greater than  198.70 cm is 0.7917.

c)

The normal distribution be used in part (b), even though the sample size does not exceed 30 since the parent population from which the sample has be obtained is Normal.

5104.38 inches

step-by-step explanation:

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.