STATISTICAL TECHNIQUES AND TOOLS
TESTS OF SIGNIFICANCE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
the population standard deviation is known.
|
|
|
the population distribution is approximately Normal.
|
|
|
the data can be regarded as a random sample from the population.
|
|
|
np and n(1-p) are both at least 10.
|
|
|
all values in the sample are within two standard deviations of the mean.
|
Detailed explanation-1: -The conditions required to conduct a t-test include the measured values in ratio scale or interval scale, simple random extraction, homogeneity of variance, appropriate sample size, and normal distribution of data.
Detailed explanation-2: -Use the t distribution for inference of the sample mean when observations are independent and nearly normal. You may relax the nearly normal condition as the sample size increases. For example, the data distribution may be moderately skewed when the sample size is at least 30.
Detailed explanation-3: -You must use the t-distribution table when working problems when the population standard deviation () is not known and the sample size is small (n<30). General Correct Rule: If is not known, then using t-distribution is correct.