Question

solve the following and mark the correct statement.

i)

In which case could the sampling distribution of sample means be expected to be normally distributed?

A) The parent population is skewed, the sample size is 20.

B) The parent population is jumbled, the sample size is 20

C) The parent population is jumbled, the sample size is 50.

D) The parent population is uniform, the sample size is 20.

ii)

Recent English test scores were approximately normally distributed with a mean of 60 and a standard deviation of 9. A random sample of 144 scores was taken. Using a TI‐84, what is the probability the sample mean is between 58.5 and 61.5?

A) Normalcdf(58.5, 61.5, 60, 0.75)

B) Normalcdf(58.5, 61.5, 60, 9)

C) Normalcdf(58.5, 61.5, 144, 0.75)

D) Normalcdf(58.5, 61.5, 144, 9)

iii)

A sample of 625 vehicles in Qatar was taken. The mean age was 3.5 years with a standard deviation of 0.5 years. What is the point estimate for the population mean?

A) 0.02

B) 0.5

C) 3.5

D) 625

iv)

Which is an example of cluster sampling?

A) 1% of the population of each school in Qatar is sampled.

B) A random sample of schools in Qatar is selected, then 5% of each school

population is sampled.

C) A student in a school is randomly selected, then every fifth student is selected.

D) The names of all students in a school are placed in a bin, then 50 are randomly

selected.

v)

Which is an example of biased sampling?

A) The dean decides to start with the second student on the enrolment, and then picks every fifth student.

B) The dean places the name of each faculty in a bag, then randomly selects three.

C) The dean uses a random number generator to select 5% of the student

population.

D) The dean uses a random number generator to select one student from the

enrolment, and starting from there selects every fourth student.

vi)

Yousif plans to take a sample of 5 students from his statistics class of 20. How many different samples are possible?

A) 5

B) 20

C) 15 504

D) 1 860 480

Answer 1