Statistics and Probability Answers

The high school sports coordinator is asked if soccer players are doing as well academically as the other student athletes. From the previous study, the GPA for student athletes is 3.10. After the intervention to help improve GPA of student athletes, the sports coordinator randomly samples 20 soccer players and finds that the average GPA of the sample is 3.18 with a sample standard deviation of 0.54.

A sports trainer wants to know whether the true average time of his athletes who do 100-meter sprint is 98 seconds. He recorder 18 trials of his team and found that the average time is 98.2 seconds with a standard deviation of 0.4 second

The ABC Company has developed a new cellphone model. The engineering department claims that its battery lasts for 4 days. In order to test this claim, the company selects a random sample of 100 new cellphones so that this sample has a mean battery life of 2.5 days with a standard deviation of 1 day. 

Newborn babies are more likely to be boys than girls. A random sample found that 13,173 boys were born among 25,468 newborn children. The sample proportion of boys was 0.5172. Is this sample evidence that the birth of boys is more common than the birth of girls in the entire population? Use 95% confidence level.

what is the mean and variance of samples of three cards are drawn random from a population of seven cards numbered 1 to 7

Which of the following statements is NOT considered as continuous random variable?

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1 point

The number of male athletes.

The weight of new-borne each year in a hospital.

The average amount of electricity consumed per household in a month.

The amount of paint utilized in a building project.

1. A population has a mean of 90 and a standard deviation of a 10. A random sample of 20 is drawn from this population. Find standard deviation of sampling distribution of sample means.

2. Suppose samples of size 10 are drawn from a population consisting of 18 measurements with the mean of 26 and standard deviation of 8. What is the mean of the sampling distribution of sample means?

3. What is the finite population correction factor if the size of the population is 150 and the sample size is 75?

QUESTION 26

A local fire station receives on average 8.5 emergency telephone calls per hour. Assume that

these calls are Poisson distributed. Calculate the probability that

(a) the fire station will get nine calls during one hour. (2)

(b) the fire station will get five to seven (inclusive) calls during one hour. (3)

(c) the fire station will get at least 4 calls during one hour. (3)

(d) the fire station will get more than 6 calls during one hour.

A librarian of a school claims that all their senior high school students read an average of 10 books a month. A random sample of senior high students read an average 12 books. The confidence statement is 95%.