Mean and Median
The relationship between the mean and the median in a right-skewed distribution.
What is mean is greater than the median
Definition of range
max-min
Kyle's school has 145 seniors, and his class rank is 11th. What is his percentile?
92nd
P(z<1.6) =
.945
Which is explanatory, and which is response?
Football teams win-loss record/ Football teams passing yards per game
Pass yards = explanatory
win-loss = response
The definition/interpretation of standard deviation
What is the average distance of each observation from the mean?
What are two differences between a bar graph and a histogram?
space between bars, x-axis is interval for histogram, x-axis is category for bar graph
What is the z-score for Johnny's test grade is he received a 94, and the class had a mean of 80 and a standard deviation of 6
2.33
P(-1.3 < z < -.1) =
.363
Interpret what it means to have a correlation coefficient (r) of .75
Moderate, positive linear relationship
If the mean of 5 test scores is an 81, and we know four of the scores to be 60, 75, 90, and a 92, what must the fifth test score be?
What is an 88
What will a histogram of test scores most likely look like if the test was "easy"?
Skewed left
The mean score on the SAT was 1690 with a standard deviation of 240. Tom's z-score was -.75. What was his SAT score?
1510
N(20,2)
Find the area between 19.17 and 22.9
.5874
LSRL: y = 2.5x - 1.7 (x = texts per day, y = snaps per day)
Predict how many texts a person would have sent if they sent 50 snaps
About 21
If an entire set of data is increased by "b", what happens to the mean, sd, median, IQR, and range?
Stays same: sd, IQR, range
Increases by "b": mean and median
List two ways a bar graph can be deceptive/misleading
wider/narrower bars, doesn't start at 0
N(45,7). What percent of data falls between the interval of 38 and 59?
About 81.5% or .815
What is the z-score that has an area of 74.3% of data to the left?
.653
Find the LSRL and the r value of the data:
x: 1 2 3 4 5 6 7 8 9 10
y: 19 17 17 18 16 15 13 12 8 6
y = -1.3394x + 21.467
r = -.9361
What is the Q1 of this data set?
1, 5, 5, 6, 9, 10, 15, 19, 21, 22, 22, 22, 22, 27
What is 6
What is the interval of numbers for which a data point could fall for this set of data, and not be an outlier? Does this data set have any outliers?
5 # Summary: 14, 30, 32, 41, 58
(13.5 - 57.5), 58 is an outlier
What does the empirical rule state? (BE SPECIFIC!!)
For any approximately normal distribution, about 68% of observations fall within 1 SD of the mean. 95% fall within 2 SD from the mean, and 99.7% of observations fall within 3 SD from the mean.
N(48, 18.1)
What value has 39% of observations above it?
53.056
LSRL: y = 46.6 + .41x (x = grade on midterm, y = grade on final)
Interpret the slope and y-int in context
For every 1 point increase on their midterm, we can predict an increase of .41 on their final
If a student scored a 0 on their midterm, we can predict a grade of about a 47 on their final