Question

1)The distribution of log-cell counts of red blood cells for women age 25-30 is approximately normally distributed with µ=1.5 cells/microliter and σ=0.1cells/microliter. Which of the following is true? Question 8 options:

P(1.5 - .02 < X < 1.5 + .02) = .68

P(1.5 - .02 < X < 1.5 + .02) = .95

P(1.5 - .02 < X < 1.5 + .02) = .9974

2) which statements are true about Normal random variable X (X~N(μ , σ ))? (Choose ALL that apply) Question 6 options:

X is continuous random variable

X is discrete random variable

Completely determined by μ and σ Symmetrical about μ

Has 99.74% of observations within 2 sigmas from the mu

3) Two events A and B are mutually exclusive if [choose all that apply]: Question 4 options:

A and B have no outcomes in common.

the Union of A and B is an empty space.

the Intersection of A and B is an empty space.

A and B are independent.

Answer 1

1) The empirical rule states that for a normal distribution:

68% of the data will fall within one standard deviation of the mean.

95% of the data will fall within two standard deviations of the mean.

99.7% of the data will fall within three standard deviations of the mean.

Answer: P(1.5 - .2 < X < 1.5 + .2) = .95

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2) All that apply:

• X is continuous random variable
• Completely determined by μ and σ Symmetrical about μ

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3) All that apply:

• A and B have no outcomes in common.
• The Intersection of A and B is an empty space.