1.a.A study of commuting times reports the travel times to work of a random sample of 1043 employed adults in Chicago. The mean is x = 34.0 minutes and the standard deviation is s = 48.9 minutes. What is the standard error of the mean? (Round your answer to four decimal places.) minutes
Inverse Normal Distribution
The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of two parameters.
Mean, Median, Mode
It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency or measure of central tendency is a central or typical value for a probability distribution.
Z-Scores
A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow comparison between two scores that belong to different normal distributions.
1.a.A study of commuting times reports the travel times to work of a random sample of 1043 employed adults in Chicago. The
minutes
b.Five hundred sixteen (516) homes in a certain southern California community are randomly surveyed to determine if they meet minimal earthquake preparedness recommendations. One hundred seventy-five (175) of the homes surveyed met the minimum recommendations for earthquake preparedness and 341 did not.
Find the point estimate for the population proportion of homes that do not meet the minimum recommendations for earthquake preparedness. (Round your answer to four decimal places.)
c.A researcher is testing the effects of plant food on plant growth. Nine plants have been given the plant food. Another nine plants have not been given the plant food. The heights of the plants are recorded after eight weeks. The populations have normal distributions. The following table is the result. The researcher thinks the food makes the plants grow taller.
| Plant Group | Sample Mean Height of Plants (inches) | Population Standard Deviation |
|---|---|---|
| Food | 16 | 2.5 |
| No food | 14 | 1.5 |
At the 1% significance level, what is your conclusion?
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