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There are 20 computers in a store. Among them, 15 are brand new and 5 are refurbished. Six computers are purchased for a student lab. From the first look, they are indistinguishable, so the six computers are selected at random. Compute the probability that among the chosen computers, two are refurbished.
1. A normal distribution of BMCC MAT51 scores has a standard deviation of 1.5. Find the z-scores corresponding to each of the following values:
a. A score that is 3 points above the mean.
b. A score that is 1.5 points below the mean.
A farmer is trying out a planting technique that he hopes will increase the yield on his pea plants. The
average number of pods on one of his pea plants is 145 pods with a standard deviation of 100 pods. This
year, after trying his new planting technique, he takes a random sample of 35 plants and finds the
average number of pods to be 147. He wonders whether or not this is a statistically significant increase.
i. What would the null and alternative hypotheses be for this scenario?
ii. What would the standard error be for this particular scenario?
iii. Describe in your own words how you would set the critical regions and what they would be at
an alpha level of .05.
iv. Test the null hypothesis and explain your decision
Given the six-element population 8,12,15,19,21, 25, 32, and 36. How many samples of size 2 can be
drawn, without replacement from this population? Compute the sampling distribution of the mean for
samples of size 2. Compute the mean and standard deviation of this distribution. Also verify the results.
The joint probability mass function of (X,Y) is p(x, y) = k(2x + 3y) ; x = 0,1,2; y = 1,2,3. (i)
Find the marginal distributions. (ii) Find P(X = xi / Y = 2) (iii) Find P[X +Y > 3] .
a) A survey of the adults in a town shows that 8% have liver problems. Of these, it is also
found that 25% are heavy drinkers, 35% are social drinkers and 40% are non-drinkers. Of
those that did not suffer from liver problems, 5% are heavy drinkers, 65% are social
drinkers and 30% do not drink at all. An adult is chosen at random, what is the probability
that this person
i. Has a liver problems? (3 Marks)
ii. Is a heavy drinker (2 Marks)
iii. If a person is found to be a heavy drinker, what is the probability that this person
has liver problem? (2 Marks)
iv. If a person is found to have liver problems, what is the probability that this person
is a heavy drinker? (2 Marks)
v. If a person is found to be a non –drinker, what is the probability that this person has
liver problems. (
a) State the null and alternative hypothesis for a test to determine the validity of the claim
b) Identify left, right, or two-tailed test type
i. The 2011 average service time for Fast Fatz Burgers was 56 seconds. The store manager claims that the 2012 average is more than 5 seconds faster.
ii. Speedy Solutions is a delivery company that claims all deliveries average less than 72 hours.
iii. At least 60% of Indians vote in presidential elections.
iv. Chance of developing heart attack is 40% for women.
#339914 on Dec 2023