Question

47. What happens to the mean and standard deviation of the distribution of sample means as the size of the sample decreases? 

A) The mean of the sample means stays constant and the standard error decreases. 

B) The mean of the sample means increases and the standard error stays. 

C) The mean of the sample means decreases and the standard error increases. 

D) The mean of the sample means stays constant and the standard error increases. 

48. Find the critical value ze that corresponds to a 95% confidence level. 

A) +2.573 B) +1.645 C) ±2.33 D) ±1.96   

49. Find the margin of error for the given values of c, σ, and n. c=0.9s, σ=0.78, n=150 

A) 0.08 B) 0.15 C) 0.11  D) 0.12

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 

50. Find the z-score that corresponds to the given area under the standard normal curve. 

Answer 1

47)

When sample size decreases then......

Answer : option "D" is correct.

The mean of the sample mean stay constant and standard error inecreases.

48)

95% confidence level at alpha=5% = 0.05

Then, critical value is Zc= $\large \pm$ 1.96

Answer : option "D" is correct.

49)

, n=150,

σ 0.78

c= 0.98 then critical value is Zc = 2.33

Therefore, the margin of error (E) is,

E =

Vn Tl

E =

2.33 0.78 V150

E = 0.15

Answer : option "B" is correct.

50)

Therefore, P(Z > z ) = 0.0011

So, 0.0011 this area probability gives a value of z score is,

z = 3.06