z scores
This score tells you how many standard deviations a value is from the mean
What is a z-score?
This measures how much sample means tend to vary from the population mean.
What is standard error?
Difference between a sample statistic and the population parameter.
What is sampling error?
Most scores fall near this location on the curve.
What is the mean?
A student says: “A z-score of -1 means the score is one point below the mean.”
What is confusing points with standard deviations?
A z-score of 0 means the score is located here.
What is exactly at the mean?
Formula for standard error of the mean.
What is σM=σ/sqrtn
If sample mean = 52 and population mean = 50, sampling error equals this.
What is +2?
About 68% of scores fall within this many SDs of the mean.
What is ±1?
A student says larger samples create larger standard error.
What is false, larger samples reduce standard error?
If a z-score is +2, the raw score is located where?
What is 2 standard deviations above the mean?
As sample size increases, standard error does this.
What is decreases?
Random sampling helps reduce this kind of bias.
What is selection bias?
About 95% fall within this many SDs.
What is ±2?
A student says a z-score of 0 means no score exists.
What is false, it means the score equals the mean?
If a score is below the mean, its z-score will be this.
What is negative?
A small standard error means sample means are this.
What is more consistent / clustered together?
Sampling error gets smaller when this increases.
What is sample size?
A z-score of +1.00 corresponds to being above what percent of scores roughly?
What is 84%?
A student uses sample mean in place of population mean in the population z formula.
What is using the wrong parameter?
Formula for a population z-score.
What is z= x-μ/σ
If population SD = 12 and n = 9, standard error equals this.
What is 4?
Sampling error is expected even when sampling is perfectly random because of this.
What is chance variation?
A z-score of -2.00 is in which tail?
What is the left tail?
A student says negative z-scores are bad scores.
What is false, they only indicate below average?