the problem as) songs is taken from the ength will be less than 3.5 minutes? Rou

Question

the problem as) songs is taken from the ength will be less than 3.5 minutes? Round to the A) 0477 B) 0.155 C) 0.023 D) 0.345 20 Suppose that the average contry sonth s nonormally distributed. Find the probability tha population will be less than 4.20 minutes. Round to the of 1.10 minutes. It is known that song length is not normally distributed. Find the probability that a single randomly selected song from the nearest thousandth. A) This probability cannot be determined because we do not know the distribution of the B) 0.006 C) 0.068 D) 0.494 21) Which of the following statements is true about the t-distribution? A) For large sample sizes, the t-distribution has the same properties as the normal curve B) Like the Normal distribution, the t-distribution is symmetric for small n. C) For small sample sizes, the t-distribution has the same properties as the normal curve. D) Since population standard deviation is usually unknown, the standard error uses the sample standard deviation to estimate population standard deviation. Use the following information to answer the question. Many couples believe that it is getting too expens average" wedding in the United States. According to the website www.costofwedding.com, the average wedding in the U.S. in 2009 was $24,066. Recently, in a random sample of 40 weddings in the US. it wa average cost of a wedding was $23,224, with a standard deviation of $2.903. On the basis of this, a 95% interval for the mean cost of weddings in the U.S. is $22,296 to $24,152 B) No 22) Does the confidence interval provide evidence that the mean cost of a wedding has decreased? A) Yes

Explanation / Answer

Question 19

Average pop song length in America = 4 min

standard deviation = 1.25 min

standard error of sample mean se0 = /sqrt(n) = 1.25/sqrt(25) = 1.25/5 = 0.25

Pr(x < 3.5 ; 4 ; 0.25)= ?

t = (3.5 -4)/0.25 = -2

p- value = TDIST (t < -2 ; dF = 24; one tailed) = 0.028

(option c is correct)

Question 20

Average country song length in America = 4.75 min

standard deviation   = 1.10 min

Here as we talked about only one sample as we donot know the distributon of the population. Option A is correct.

Question 21

Here option A is correct as for large sample sizes, the t - distribution has the small propoerties as the normal curve.

Question 22

As the confidence interval consist the value give by website $ 24,066 so we cannot say that the mean cost of wedding has been decreased. The answer is No.

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