Mean, Median, Mode, SD
Calculate the mean of this data set:4,6,8,10,12
8
What is a z-score?
The number of standard deviations above or below the mean.
Determine the percent of data to the left of the z score: z= 1.2
88.5%
a survey reports that 60% of students prefer pepperoni pizza, with a margin of error of +/- 4%. What is the confidence interval?
56%-64%
Find the mean median and mode: 3, 5, 7, 10, 5
mean: 6
median: 5
mode: 5
A student scores 80% on a test with a mean of 70% and a standard deviation of 10. Find the z-score.
z=1
A normal Distribution has a mean of 50 and a standard deviation of 10. What percentage of values fall between 30 and 70?
Draw a picture.
normalcdf(30,70,50,10)=95%
A poll was conducted about an upcoming election. The results are considered accurate within +/-3.4% points, 19 out of 20 times. What is the confidence level?
19/20=95%
The mean of 5 test scores is 80. Four scores are 70, 75, 85, 90. Find the missing test score.
80
A distribution has a mean of 100 and a standard deviation of 15. What is the data value if the z-score is 2?
x=130
On a standard normal curve, 64% of the data is above the z-score. What is the z-score? Draw a sketch.
invNorm(0.36,0,1,left) or invNorm(0.64, 0,1,right)
z=-0.358
The confidence interval for people who voted for conservative was 38%-45%.
The confidence interval for people who voted for NDP was 27%-37%.
Can we say with 95% confidence that the percentage of people who voted for conservative was higher than NDP?
Yes, there is no overlap so we can make that conclusion.
Calculate the standard deviation.
L1: 2,4,5,7
L2: 1,5,6,8
1.46
James scores 85% on a test with mean 75% and standard deviation of 5%. Olivia scores 90% on a test with a mean of 70% and standard deviation of 10%. Who performed better relative to their class?
They performed equally well compared to the rest of the class because both their z scores are 2.
Higher z-score=did better compared to the average
If the area to the right of the positive z-score is 31%, what is the z-score? Draw a picture.
z=0.495 = 0.5
Interval: 4.6-5.4
Confidence Level: 96%
Margin or Error: +/-0.4
Amanda's scores an average of 15 points per game with a standard deviation of 3 points.
Brian scores an average of 20 points per game with a standard deviation of 5 points.
Who is the most consistent point scorer?
Amanda because her standard deviation is less thus her score is closer to the mean
If a student got 70% on a test and the average was 65%, and the number of standard deviations is 1.2 above the mean, what is the standard deviation?
4.17
The ages of players on a hockey team are normally distributed with a mean of 25 years and a standard deviation of 4 years. The team has 18 players.
How many players would be between the ages 20 and 31? Round to the nearest whole number.
82.75% so 15 players
If the area between the mean (150) and the data point (140) is 0.4 find the standard deviation to the nearest tenth.
7.8