A random sample of n 20 winter days in Denver gave a sample mean pollution lindex x, 43. Previous studies show that o, 10, For Englewood (a suburb of Denver), a random sample of n,19 winter days gave a sample mean pollution Index of xy 37. Previous studies show that o, 13. Assume the pollution index is normally distributed in both Englewood and Denver. Do these data indicate that the mean population pollution index of Englewood is different (either way) from that of Denver in the winter? Use a 1% level of significance. (a) what is the level of significance? state the nuil and alternate hypotheses. O Ho: Hi Hai H HHa (b) what sampling distribution wtll you use? what assumptions are you making? O The Student's t. we assume that both population distributions are approximately normal with unknown standard deviations. O The Student's t. We assume that both population distributions are approximately normal with known standard devtations. O The standard normal, We assume that both population distributions are approximately normal with unknown standard deviations. O The standard normal. We assume that both population distributions are approximately normal with known standard deviations. What is the value of the sample test statistic (Test the difference ,-H. Round your answer to two decimal places.) (c) Find (or estimate) the P.value. (Round your answer to four decmal places.) Sketch the sampling distribution and show the area corresponding to the Pvalue. -2
Correlation
Correlation defines a relationship between two independent variables. It tells the degree to which variables move in relation to each other. When two sets of data are related to each other, there is a correlation between them.
Linear Correlation
A correlation is used to determine the relationships between numerical and categorical variables. In other words, it is an indicator of how things are connected to one another. The correlation analysis is the study of how variables are related.
Regression Analysis
Regression analysis is a statistical method in which it estimates the relationship between a dependent variable and one or more independent variable. In simple terms dependent variable is called as outcome variable and independent variable is called as predictors. Regression analysis is one of the methods to find the trends in data. The independent variable used in Regression analysis is named Predictor variable. It offers data of an associated dependent variable regarding a particular outcome.
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