1.
Normal distribution curve is a) Continuous. b) Positively skewed. c) Negatively skewed. d) All of the above.
2.
The properties of normal distribution a) mean = median = mode b) mode > mean c) median < mean d) all of the above.
3.
A normal distribution curve is ……… a) Bell shaped b) J- shaped c) U- shaped d) S- shaped
4.
The total area under the normal distribution curve is equal to a) 1 b) 0 c) 0.5 d) 0.8000
5.
Normal distribution curve is symmetrical about
A) 0
B) μ
C) σ
D) 1
6.
The standard normal distribution with a mean and standard deviation, respectively
are……
A) mean = 1, standard deviation = 0
B) mean = 0, standard deviation = 1
C) mean = -1, standard deviation = 1
D) mean = 1, standard deviation = -1
Statistics
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1The mean is 15.2 and the variance is 0.81. Find P(x>16)? Assume the variable is normally distributed
A) 0.8133
B) 0.8106
C) 0.8078
D) 0.1867
2The average number of calories in a chocolate bar is 225. Suppose that the distribution of calories is approximately normal with σ = 10. The probability that a randomly selected chocolate bar will have less than 200 calories is
A) 0.0062
B) 0.9938
C) 0.9876
D) 0.3023
3The average score for a biology test is 77 and the standard deviation is 8.
Which percent best represents the probability than any one student scored between 61 and 93 on the test
A) 68%
B) 95%
C) 99.5%
D) 34%
4Find two z values so that 90.50% of the middle area is bounded by them?
A)
± 1.67
B)
± 0.45
C) ± 1.02
D)
± 1.73
5Find the P(-0.55<Z<0.55)
A) 0.4476
B) 0.9000
C) -0.9000
D) 0.4176
6Find the z value if the area shaded below is equal to 0.9875: a)
– 2.24 b) 1.05 c) 2.42 d) 0.5
Statistics
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7The standard deviation of the sample means will be: a) Equal the population standard deviation. b) The population standard deviation divided by the square root of the sample size. c) The square root of the population standard deviation. d) More than the standard deviation of the population.
8In a normal distribution find the σ when µ=110 and 2.87% of the area lies to right of 112. a) 4.52 b) 4.25 c) 1.05 d) 2
9To qualify for a university, candidates must score in the top 20% on a general abilities test. The test has a mean of 150 and a standard deviation of 25. Find the lowest possible score to qualify? Assume the test scores are normally distributed.
A) 162
B) 171
C) 175
D) 129
10. The average time it takes a group of adults to complete a test is 46.2 minutes and the standard deviation is 8 minutes. Assume the variable is normally distributed. If 50 randomly selected adults take the test, find the probability that the mean time it takes the group to complete the test will be less than 47 minutes.
A) 0.7611
B) 0.2389
C) 0.5398
D) 0.9999
11If a sample size is 9 and the standard deviation is 2.3 then Sampling error
A) 2.3
B) 3
C) 0.76
D) 0.25
Statistics
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