We want to compare the mean salaries of elementary school teachers in Edmonton and Calgary. Based on the data he collected, we computed the following statistics in Table 1. Edmonton Calgary sample mean x1 = 45000 x2 = 53000 sample standard deviation s1 = 2400 s2 = 1150 sample size n1 = 400 n2 = 600 Table 1: Summary of the salaries of elementary school teachers in Edmonton and Calgary Let 1 = the mean salary of elementary school teachers in Edmonton 2 = the mean salary of elementary school teachers in Calgary: 26. A 90% con dence interval for the di erence of the mean salaries of elementary school teachers in Edmonton and Calgary (1 ? 2) is (a) from -8253.333 to -7746.667 (b) from -8212.485 to -7787.515 (c) from -8165.453 to -7834.547 (d) from -8212.099 to -7787.901 (e) from -8165.195 to -7834.805
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.
We want to compare the mean salaries of elementary school teachers in Edmonton and Calgary.
Based on the data he collected, we computed the following statistics in Table 1.
Edmonton Calgary
sample mean x1 = 45000 x2 = 53000
sample standard deviation s1 = 2400 s2 = 1150
Table 1: Summary of the salaries of elementary school teachers in Edmonton and Calgary
Let
1 = the mean salary of elementary school teachers in Edmonton
2 = the mean salary of elementary school teachers in Calgary:
26. A 90% con dence interval for the di erence of the mean salaries of elementary school teachers
in Edmonton and Calgary (1 ? 2) is
(a) from -8253.333 to -7746.667
(b) from -8212.485 to -7787.515
(c) from -8165.453 to -7834.547
(d) from -8212.099 to -7787.901
(e) from -8165.195 to -7834.805
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