z Confidence intervals for the Mean - Page 2
Questions
- In a class test where the mean was 62% and the standard deviation 12.6%, Jan received 74%. What is her result a a z-score?
- A random sample of 10 children found that their average growth for the first year was 9.8 inches. What is the 95% confidence interval of the population mean for growth during the first year?
- The average time a subscriber spends reading the local newspaper is 49 minutes. For the 10% who spend the most time reading the paper, how much time do they spend?
- The class average on a math test was 75.5 and the standard deviation was 4.2. What is the z-score for a test score of 81?
- What is the z-value of something that has an area of .8051 under the standard normal curve to its right?
- What is area under the normal curve between #z=-2.0# and #z=-1.0#?
- If mean IQ is #105# and standard deviation is #20#, what is the probability that a randomly selected adult has an IQ between #85# and #125#?
- How do I find #z# for a given confidence level #alpha#?
- A normal distribution has a mean of 51 and a standard deviation of 4. At which interval centered at the mean do 55% of values drawn from the distribution lie?
- In a simple, random sample of 600 people, 418 prefer cheeseburgers. What is the 95% confidence interval?
- Out of 786 students surveyed, 582 of them hate smoking cigaretes. Find the confidence interval corresponding to 96% degree of confidence?
- What z score represesnt 97%? interpret result
- Find the z-scores for which 49.72% of the standard normal distribution's area lies between -z and z?
- Find the value of z so that the area under the standard normal curve from 0 to z is 0.4761 and z is positive?
- Given that Z is a standard normal random variable, find the following. Hint draw a picture! P(Z>0.47) ?
- Find the z-score such that the area under the standard normal curve to the left Is 0.59?
- How do you Find the z-scores that separate the middle 85% of the distribution from the area in the tails of the standard normal distribution?
- Find the area under the standard normal curve between z=0 and z=3?
- The mean of a set of data is -2.14 and its standard deviation is 3.94. Find the z score for a value of 5.40?
- How to find 95% margin of error from 95% confidence interval?