syntax/definitions
what is the difference between a sample and population
sample is a subset while population is all
Remember the Taylor Swift and Kim K twitter fight about the famous lyric? Buzzfeed put out a poll asking what side people were on. of the 980 people that voted, 559 of them were men in support of Kim K. What percentage is this?
559/980 = 57.04%
what is the formula for percent proportion?
part/whole = proportion
Consider the following data set:
-18 -11 -10.5 -3 2.25 9 14 18.75 20.5
using your calculator, find the mean and SD (give your syntax)
stat- edit-l1- stat calc 1varstat
mean 2.4444
sx= 13.9837
what are the key parts to describing a distribution?
Shape, Center, Variability and outliers
It's the end of the semester! you have one more test before grades close and you have received scores of: 20, 65, 80, 85 and 95. Find the mean of your scores.
(20+65+80+85+95) / 5 = 69
Define Standard deviation, provide its symbol and formula.
measure of the horizontal spread aka deviation of a typical data p point from the mean
s
square root (summation (x-xbar)^2 / (n-1)
you read that the mean age children take their first steps is 12 months...you're not convinced. you take a random sample of 5 children and find that the ages at which they took their first steps were 10 12 14 12 and 11 months. Find the mean and the SD for your data. (if you use the calc. include your syntax)
stat-edit-l1-stat-calc-1 var stat
mean 11.8
SD= 1.4832
state the percentages of the empirical rule.
68-95-99.7
A z-score measures how many standard deviations a value is above or below the mean. The formula for a z-score is (x-xbar)/s.
Hannah takes an IQ test. The test is normally distributed with a mean of 100 and a standard deviation of 15.
She scores a 75. what is the z-score.
(70-100)/15= -2