Show:
I Just Want to be Normal
What are(a) the Chances?
Find that Probability
Find Zee Score
Mean of Means
100
I am the graph of a distribution. The total area underneath me is 2. Why aren't I normal?
What is "the area underneath you should be 1."
100
The test scores in a large college lecture class are normally distributed with a mean of 72 and a standard deviation of 8. What is the probability that a randomly selected student scored higher than 83? Round your answer to the nearest thousandth.
What is "0.085"
100
Movie length times are normally distributed with a mean of 130 minutes and a standard deviation of 21 minutes. If you randomly select a movie, what is the probability that it is more than 100 minutes long? Round your answer to the nearest thousandth.
What is "0.923."
100
The mean score on a standardized test is 512, with a standard deviation of 94. Find the z-score of a student who scored 610 on the test. Round your answer to the nearest hundredth.
What is "1.04"
100
What notation do we use to represent the mean of a sampling distribution?
What is "mu x-bar"
200
I am the graph of distribution. I have inflection points 3 standard deviations away from my mean. Why aren't I normal?
What is "you should have inflection points 1 standard deviation away from your mean."
200
Find the area under the standard normal curve between z=-1.3 and z=1.3. Round your answer to the nearest thousandth.
What is "0.806"
200
Find P(z>-0.7). Round your answer to the nearest thousandth.
What is "0.758"
200
Find the z-score that corresponds to a cumulative area of 0.429 under the normal curve. Round your answer to the nearest thousandth.
What is "-0.179"
200
A population has a mean of 73 and a standard deviation of 18. Find the mean AND standard deviation of a sampling distribution of sample means with sample size 24. Where applicable, round your answer to the nearest hundredth.
What is "the mean is 73 and the standard deviation (standard error) is 3.67"
300
I am the graph of a distribution. About 80% of the area underneath me lies within 2 standard deviations of my mean. Why aren't I normal?
What is "about 95% of the area underneath you should lie within 2 standard deviations of your mean."
300
The annual salaries of statisticians are normally distributed with a mean of $80,000 and a standard deviation of $15,000. In a group of 100 statisticians, how many would you expect to earn between $70,000 and $90,000 per year? Round your answer to the nearest statistician.
What is "50."
300
Find P(z<-1.4 or z>1.4). Round your answer to the nearest thousandth.
What is "0.162"
300
Find the z-score such that the area to the right under the normal curve is 0.868. Round your answer to the nearest thousandth.
What is "-1.117"
300
The mean height of students at a school is 67 inches, with a standard deviation of 3 inches. A random sample of 35 students is selected. What is the probability that the mean height of the sample is greater than 68 inches? Round your answer to the nearest thousandth.
What is "0.024"
400
I am a sampling distribution of means. My parent population is not normally distributed. I was formed using samples of size 15. Why aren't I normal?
What is "you were not formed using samples of size 30 or more" OR "your parent population is not normally distributed."
400
The weights of newborn babies are normally distributed with a mean of 7.6 lbs and a standard deviation of 1.1 lbs. In what percentile is a newborn baby who weighs 7 lbs? Round your answer to the nearest whole number.
What is "the 29th percentile."
400
The number of years that Walnut Hill students have studied their art form are normally distributed with a mean of 8 years and a standard deviation of 3.5 years. If you randomly select a sample of 25 Walnut Hill students, what is the probability that they have studied their art for an average of at least 9 years? Round your answer to the nearest thousandth.
What is "0.077"
400
Find the z-scores such that 25% of the area under the normal curve lies between -z and +z. Round your answer to the nearest thousandth.
What is "-0.319 and +0.319"
400
Starbucks claims that a grande-sized coffee has a mean of 16 ounces and a standard deviation of 0.85 ounces. You randomly select a sample of 100 grande coffees and measure the mean volume to be 15.9 ounces. Assuming that Starbuck's claim is correct, what is the probability that the mean of the sample is 15.9 or less? Round your answer to the nearest hundredth.
What is "0.12"