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WorksheetsApproximately Normal Distributions of Sample Means
Total questions: 25
Worksheet time: 6hrs 15mins
The Central Limit Theorem states that if a population is (approximately) normal OR the sample size is greater than or equal to ____, then the associated sampling distribution is approximately normal.
30
20
500
80
What is the mean of the sampling distribution?
What is the standard deviation of the sampling distribution?
The weight distribution of a certain animal is approximately normal with a mean of 1,000 lbs. and a standard deviation of 25 lbs. What is the probability that the mean weight of 25 of these animals selected at random and with replacement is greater than 1,010 pounds?
65.54%
97.72%
2.28%
34.46%
Unknown - we can't assume the shape of the sampling distribution
The mean and standard deviation of a population are 200 and 20, respectively.
If 25 data points are selected from this population at random and with replacement, what is the probability that they have a sample mean of less than 190?
69%
0.6%
31%
99%
Unknown - we can't assume the shape of the sampling distribution
The weights of horses are approximately normal with a mean of 1,500 lbs. and a standard deviation of 30 lbs. What is the probability that the mean weight of 36 randomly selected horses is greater than 1560 pounds?
[Hint: 36 isn't even close to 5% of all the horses in the world.]
65.54%
97.72%
~0%
34.46%
Unknown - we can't assume the shape of the sampling distribution
Increasing the sample size of an opinion poll will reduce the...
bias of the estimates made from the data collected in the poll.
variability of the estimates made from the data collected in the poll.
variability of opinions in the sample.
variability of opinions in the population.
If 64 data points are selected at random from this population, what is the probability that the mean value of these data points will be between 195 and 200?
If 100 data points are selected at random from this population, what is the probability that the mean of this sample will be greater than 202?
A classroom has 30 students. The mean height of students in this classroom is 63 in. with a standard deviation of 4.6 in. Assume these heights approximate a normal distribution.
If ten students are selected at random and without replacement from this classroom, what is the probability that the mean height of the selected students will be less than 62 in.?
0.2033
0.2451
0.1170
0.2420
If fifteen people enter this elevator, what is the probability that the maximum safe weight is exceeded?
In which situation would the Finite Correction Factor be needed?
n=40, N=200, selecting with replacement
n=40, N=200, selecting without replacement
n=40, N=2,000, selecting with replacement
n=40, N=2,000, selecting without replacement
Describe the distribution of the data set represented by this histogram.
The weights of weightlifters are approximately normal in distribution with a mean of 340 lbs. and a standard deviation of 35 lbs.
Given this, which of the following is more likely?
A randomly-chosen weightlifter will weigh less than 350 lbs.
The mean weight of 30 randomly-chosen weightlifters will be less than 350 lbs.
Both are equally likely
Not enough information to tell.
