7. The average age of residents in a large residential retirement community is 6

Question

7. The average age of residents in a large residential retirement community is 69 years with standard deviation 5.8 years. A simple random sample of 100 residents is to be selected, and the sample mean age of these residents is to be computed. We know the random variable has approximately a Normal distribution because: of the central limit theorem. the population from which we're sampling has a Normal distribution. of the law of large numbers. of the 68–95–99.7 rule.

8.

0.805.

9.

The average age of residents in a large residential retirement community is 69 years with standard deviation 5.8 years. A simple random sample of 100 residents is to be selected, and the sample mean age of these residents is to be computed. The probability that the average age, of the 100 residents selected is less than 68.5 years is:

0.568. 0.195. 0.043.

0.805.

9.

Suppose you're in a class of 35 students. The instructor takes a simple random sample of seven students and observes their heights. Imagine all of the different samples possible. Let X denote the tallest height in your sample. The distribution of all values taken by X in all possible samples of seven students selected from the 35 students in your class is the: probability that X is obtained. parameter. sampling distribution of X. standard deviation of values.

Explanation / Answer

8) here std error =std deviation/(n)1/2 =0.58

hence P(X<68.5)=P(Z<(68.5-69)/0.58)= P(Z<-0.862)=0.195

9)sampling distribution of X

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