A simple random sample is a sample of n observations that has the same probability of being selected from the population as any other sample of n observations.
A random sample of size 100 is taken from a population described by the proportion p = 0.60.
After examining his records from the past 10years, he finds that the scores have a mean of 76 and a standard deviation of 12.
Nonresponse bias occurs when those responding to a survey or poll differ systematically from the nonrespondents.
In cluster random sampling, the population is first divided up into mutually exclusive and collectively exhaustive groups, called clusters. A cluster sample includes randomly selected observations from each cluster, which are proportional to the cluster's size.
Information from the sample is typical of information in the population.
A population can be divided into 50 city blocks. The sample will include residents from two randomly chosen city blocks.
When testing whether the correlation coefficient differs from zero, the value of the test statistic is t20 = −2.95 with a corresponding p-value of 0.0061. At the 5% significance level, can you conclude that the correlation coefficient differs from zero?
If two linear regression models have the same number of explanatory variables, a model with an R2 value of 0.45 is a better prediction model than a model with an R2 value of 0.65.
The standard deviation of X¯¯¯X¯ (standard error of the sample mean) equals the population standard deviation divided by the square root of the sample size, or, se ( X )¯¯¯¯¯ = σn√ se ( X )¯ = σn equivalently.
B = The survey respondent is 40 years or older.
Yes, since the p-value is less than 0.05.
Yes, if two or more values in a data set occur with the most frequency and the frequency is greater than one. The table below gives the deviations of a portfolio's annual total returns from its benchmark's annual returns, for a six-year period ending in Year 6. mean = -1.67% and median = -0.56%.