A coffee manufacturer is interested in whether the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers. Assume the population standard deviation for those drinking regular coffee is 1.24 cups per day and 1.44 cups per day for those drinking decaffeinated coffee. A random sample of 49 regular-coffee drinkers showed a mean of 4.57 cups per day. A sample of 39 decaffeinated-coffee drinkers showed a mean of 5.17 cups per day. Use the 0.025 significance level. Is this a one-tailed or a two-tailed test? One-tailed test. Two-tailed test. State the decision rule. (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.) Compute the value of the test statistic. (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.) What is the p-value? What is your decision regarding H0? Reject H0. Do not reject H0. rev: 10_12_2017_QC_CS-102203, 11_21_2017_QC_CS-110078, 04_02_2018
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.
A coffee manufacturer is interested in whether the mean daily consumption of regular-coffee drinkers is less than that of decaffeinated-coffee drinkers. Assume the population standard deviation for those drinking regular coffee is 1.24 cups per day and 1.44 cups per day for those drinking decaffeinated coffee. A random sample of 49 regular-coffee drinkers showed a mean of 4.57 cups per day. A sample of 39 decaffeinated-coffee drinkers showed a mean of 5.17 cups per day.
Use the 0.025 significance level.
-
Is this a one-tailed or a two-tailed test?
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One-tailed test.
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Two-tailed test.
-
State the decision rule. (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)
-
Compute the value of the test statistic. (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)
-
What is the p-value?
-
What is your decision regarding H0?
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Reject H0.
-
Do not reject H0.
rev: 10_12_2017_QC_CS-102203, 11_21_2017_QC_CS-110078, 04_02_2018
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