# Quiz 34: Normal Distribution

Business

Q 1Q 1

Which of the following statements about the normal distribution are NOT true?
A) The normal distribution is symmetrically shaped
B) The normal distribution is centred around the mean
C) The normal distribution shows a clustering of values around the mean
D) The normal distribution is not suitable for use with continuous data

Free

Multiple Choice

D

Q 2Q 2

What name is given to a value that has been standardized?
A) Mean
B) Z-score
C) Standard Deviation
D) Variance

Free

Multiple Choice

B

Q 3Q 3

Calculate the Z-score for a value of 34 when mean = 24 and standard deviation = 4
A) 2.0
B) 2.2
C) 2.5
D) 2.8

Free

Multiple Choice

C

Q 4Q 4

If the probability that a Z-score lies between 0 and 2 is 0.452 then what is the probability that Z < 2?
A) 0.4772
B) 0.5
C) 0.9772
D) 0.0228

Free

Multiple Choice

Q 5Q 5

The diameter of holes drilled into flat-pack furniture is normally distributed with a mean of 5mm and a standard deviation of 0.15mm. If a single item of furniture has 50 holes in it, how many have a diameter of more than 5.2mm (to the nearest whole number)?
A) 5
B) 6
C) 7
D) 8

Free

Multiple Choice

Q 6Q 6

If the normal distribution is to be used as an approximation to the binomial with n = 200 and p = 0.78 what value should be used to approximate the standard deviation (1 decimal place)?
A) 5.8
B) 5.9
C) 6.0
D) 6.1

Free

Multiple Choice

Q 7Q 7

Assuming a confidence interval of 95% (z = 1.96), calculate the width of the confidence interval for n = 65, = 24.5, s = 4.5 (1 decimal place)
A) 24.5 ± 0.8
B) 24.5 ± 0.9
C) 24.5 ± 1.0
D) 24.5 ± 1.1

Free

Multiple Choice

Q 8Q 8

A sample of components made by a factory in China shows that 6 out of a sample of 50 were found to be faulty. What is the width of a 95% confidence interval (z = 1.96) for the defect rate (2 decimal places)?
A) 0.12 ± 0.06
B) 0.12 ± 0.09
C) 0.12 ± 0.12
D) 0.12 ± 0.15

Free

Multiple Choice

Q 9Q 9

Last year average wages in an Indian firm were INR 109,658, a sample of 30 employees in the same firm this year gives an average wage of INR 110,986 (standard deviation INR 1,234). Is this evidence of a significant difference in wages?
A) No, -1.96 < z < 1.96
B) Yes, they have gone down, z < -1.96
C) Yes, they have gone up z > 1.96
D) There is no evidence of a significant difference

Free

Multiple Choice

Q 10Q 10

Analysis of a sample of 50 of the second quarter sales of a Dubai fashion store shows a difference ( - ) of AED 236, z = +2.37 indicating that the difference is significant. Calculate the standard deviation of the sample (1 decimal place).
A) AED 697.3
B) AED 704.1
C) AED 723.6
D) AED 734.9

Free

Multiple Choice