Mean and median
Find the median for the heart rate of 20 year old patients.
108, 68, 80, 83, 72
median = 80
What is a standard deviation?
Rough estimate of the typical distance of the values in the dataset from the mean of the same dataset.
How do you find the sample size from a dot plot?
by counting the number of dots in the dot plot.
What do you need to construct a two way table?
2 Categorical variables.
Find the mean of the following dataset.
15,22,12,28,58,18,25,18
24.5
What is the formula for standard deviation? (Both population and sample deviations)
sample sd = ((Sum(x-mean)2)^1/2) / (n-1)
population sd =((Sum(x-mean)2)^1/2) / (n)
How do you find the sample size from a histogram?
Adding the heights of individual bars.
Construct a two way table for the following:
2 out of 7 students are male. 1 out of 2 males are freshmen and 2 of the females are freshmen.
Answer key:
What is the relationship between mean and median in left-skewed, right skewed and symmetric distribution?
mean< median
mean> median
mean ~ median
What are the steps to calculate standard deviation?
1. Find the mean.
2. Find the difference between each x value and the mean.
3. Square the answers from number 2.
4. Find the sum of the answers from number 3.
5. Use the standard deviation formula.
Find the shape, outliers and sample size of the following histogram.
sample size- 9
outliers: 9
shape: right skewed
Find the proportion of males who disagree.
0.6653
What are the effects of outliers on the mean and median of the distribution?
outliers do not effect median.
High outliers increase the mean and low outliers decrease the mean.
Calculate the sample standard deviation of the following:
108, 68, 80, 83, 72
sample sd: 13.9771
Find the mean and median of the given histogram.
median: 5
mean: anywhere between 5.5 and 6
What proportion of people who disagree are females?
0.55