Mathematics, 04.12.2019 00:31 icylaila

Fifty people in the civilian labor force are randomly selected and the sample average age iscomputed to be 36.4.(a) find a 90% confidence interval for the mean age, ? , of all people in the civilian laborforce. assume that the population standard deviation for the ages of civilian labor force is12.1 years. interpret the confidence interval.(b) it is being claimed that the mean age of the population of civilian labor force is 40. whatdo you conclude based on the confidence interval?

Answers: 3

Show answers

Answers

Answer from: svandewalle

a) The 90% confidence interval would be given by (33.594;39.206)

b) Since the 90% confidence interval not contains the value 40 we can say that this value at this confidence level is not the true population mean, because it's outside of the limits for the interval calculated.

Step-by-step explanation:

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 a

$\bar X=36.4$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=12.1$ represent the population standard deviation

n=50 represent the sample size

90% confidence interval

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

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a tabel to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Now we have everything in order to replace into formula (1):

$36.4-1.64\frac{12.1}{\sqrt{50}}=33.594$

$36.4+1.64\frac{12.1}{\sqrt{50}}=39.206$

So on this case the 90% confidence interval would be given by (33.594;39.206)

Part b

Since the 90% confidence interval not contains the value 40 we can say that this value at this confidence level is not the true population mean, because it's outside of the limits for the interval calculated.

Answer from: Quest

sadsadsadsad

step-by-step explanation:

Answer from: Quest

If is was sunny on thursday, chances are that it will be a sunny if friday depending on the degrees and temperature. your welcome!
Ineed asap. let event a= it is sunny on thursday. which event is most likely to be independent of a

Ineed asap. let event a= it is sunny on thursday. which event is most likely to be independent of a

Another question on Mathematics

Mathematics, 21.06.2019 15:00

When you arrive at the lake, your friend realises he hasn’t got any swimming trunks. you need to ride to a sports shop. the sports shop is 8350 metres away. how many metres is it to cycle there and back?

Answers: 1

Answer

Mathematics, 21.06.2019 20:30

choose the correct definition for extremo. a. end b. extra c. extract d. eventual

Answers: 2

Answer

Mathematics, 21.06.2019 21:30

In a test for esp (extrasensory perception), the experimenter looks at cards that are hidden from the subject. each card contains either a star, a circle, a wave, a cross or a square.(five shapes) as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. when the esp study described above discovers a subject whose performance appears to be better than guessing, the study continues at greater length. the experimenter looks at many cards bearing one of five shapes (star, square, circle, wave, and cross) in an order determined by random numbers. the subject cannot see the experimenter as he looks at each card in turn, in order to avoid any possible nonverbal clues. the answers of a subject who does not have esp should be independent observations, each with probability 1/5 of success. we record 1000 attempts. which of the following assumptions must be met in order to solve this problem? it's reasonable to assume normality 0.8(1000), 0.2(1000)%30 approximately normal 0.8(1000), 0.2(1000)% 10 approximately normal srs it is reasonable to assume the total number of cards is over 10,000 it is reasonable to assume the total number of cards is over 1000

Answers: 1

Answer

Mathematics, 21.06.2019 23:00

Two years ago a man was six times as old as his daughter. in 18 years he will be twice as old as his daughter. determine their present ages.

Answers: 1

Answer

You know the right answer?

Fifty people in the civilian labor force are randomly selected and the sample average age iscomputed...

Questions

Mathematics, 23.10.2020 08:01

Abigail is riding her bike down the street at 15m/s. If it takes her 60 sec to get to the end of the street, then how long is the street?...

Mathematics, 23.10.2020 08:01