Types of Displays
Shape & Vocab
Empirical/Chebyshev's
mean, variance & std dev
z-scores
100
This is a bar graph in which bars touch and show frequency. The x-axis can be labeled with class limits or midpoints.
histogram
100
This shape is when all bars of a histogram are close to the same height.
uniform
100
When data is normally distributed, what percent of data lies within one standard deviation of the mean?
68%
100
How do you find the mean of a frequency distribution?
multiply x (data value) by f (frequency). Find the sum of x(f) and divide by the total frequency.
100
True or False: A z-score can be positive or negative.
true
200
This is a line graph that shows cumulative frequency
ogive
200
This is when the data is more frequent at the lower end and trails off at the higher end.
skewed right
200
mean = 56 st dev = 4 Between what two values does 95% of data lie? (Assume the data is normally distributed)
48 - 64
200
True or False: The formula for variance is the same for a population and a sample.
False
200
True or False: A z-score above 4 is unusual.
True
300
This is a bar chart in which bar do not touch and are arranged in decreasing order.
Pareto chart
300
This is the "normal" shape or a mirror-image when split at the mean.
symmetric
300
A data display has a mean of 36. The standard deviation is 3. What percent of data lies between 36 and 39?
37.5%
300
Find the weighted mean: Test 1 82% weight 25% Test 2 74% weight 25% Quiz 1 98% weight 10% Quiz 2 95% weight 10% Project 94% weight 15% Homework 100% weight 15%
87.4%
300
Jeff scores a 78 on a test that has a mean of 84 and a standard deviation of 4. What is his z-score?
-1.5
400
This is a line graph that shows frequency. It connects to the x-axis which is labeled with class midpoints.
frequency polygon
400
In this type of distribution, the mean and mode are typically higher than the median.
skewed left
400
A data display has a mean of 12. If 88.9% of data lies between 6 and 18, what is the standard deviation?
2
400
A data set includes 20 values with the following values: x bar = 3.2 the sum of (x - x bar)^2 = 1,342 Find the variance
70.63
400
The life of a standard battery is 12 months with a standard deviation of 2 months. How long does a battery last if it has a z-score of 1.75?
15.5 months
500
This is a way of plotting paired data.
scatter plot
500
These are the midpoints between the upper class limit and the lower class limit of consecutive classes. They close any "gaps" between class limits.
class boundaries
500
A data display is normally distributed with a mean of 42 and a standard deviation of 2.5. What percent lies above 49.5%?
0.15%
500
A data set contains 8 values with the following values: mu = 4.5 The sum of (x-mu)^2 = 3156 Find the standard deviation.
19.86
500
If you get a z-score of 2 on a test, how do you compare to the rest of the class (assume a normal distribution and think percentages)?
You did better than 97.5 % of the class. Only 2.5% did better than you.
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