WGU C723 Quantitative Business Analysis Final

Hypothesis - is an assumption about a population parameter such as a mean or a proportion null hypothesis (H0) - -represents the status quo -states a belief that the population parameter is ≤, =, or ≥ a specific value -believed to be true unless there is overwhelming evidence to the contrary alternative hypothesis (H1) - -represents the opposite of the null hypothesis -believed to be true if the null hypothesis is found to be false -always states that the population parameter is >, ≠, or < a specific value two-tail hypothesis test - is used whenever the alternative hypothesis is expressed as ≠ one-tail hypothesis test - is used when the alternative hypothesis is stated as < or > Type I error - -occurs when the null hypothesis is rejected when it is true -when it occurs the producer is looking for a problem in its process that does not exist Type II error - -occurs when we fail to reject the null hypothesis when it is not true -when it occurs the customer is getting a product from a process that is not performing properly Correlation analysis - -is used to measure both the strength and direction of a linear relationship between two variables -A relationship is linear if the scatter plot of the independent and dependent variables has a straight-line pattern correlation coefficient, r - -indicates both the strength and direction of the linear relationship between the independent and dependent variables population correlation coefficient (ρ) - refers to the correlation between all values of two variables of interest in a population confidence interval for the mean - is an interval estimate around a sample mean that provides us with a range within which the true population mean is expected to lie confidence level - is defined as the probability that the interval estimate will include the population parameter of interest Student's t-distribution - is used in place of the normal probability distribution when the sample standard deviation, s, is used in place of the population standard deviation, σ probability sample - is a sample in which each member of the population has a known, nonzero, chance of being selected for the sample