Z Score - How many standard deviations you are from the mean. The higher the absolute value of the Z score, the more above or below average that value is. (A score of 1.5 means you are 1.5 standard deviations above the mean, -1.5 means 1.5 standard deviations below the mean.)
Confidence Interval - Most real world example is the margin of error in political polls. When they say: "Candidate X has 54% of voters (Margin +/- 3)." That means he actually has somewhere between 51-57% of voters. Whenever you sample, you can't be certain that your sample is going to be perfectly representative of the entire population. So, you'll always have a margin of error. The confidence interval is just a way for statisticians to say, "I am 95% sure that the value is actually within this particular range." Usually the smaller the sample, the larger the confidence interval.
If you don't understand your teacher or he/she sucks, turn to wikipedia and see if it can shed some light on the subject (Not joking).
Confidence Interval - Most real world example is the margin of error in political polls. When they say: "Candidate X has 54% of voters (Margin +/- 3)." That means he actually has somewhere between 51-57% of voters. Whenever you sample, you can't be certain that your sample is going to be perfectly representative of the entire population. So, you'll always have a margin of error. The confidence interval is just a way for statisticians to say, "I am 95% sure that the value is actually within this particular range." Usually the smaller the sample, the larger the confidence interval.
If you don't understand your teacher or he/she sucks, turn to wikipedia and see if it can shed some light on the subject (Not joking).
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