z-score Basics
What does it mean if a z-score is 0?
The data value is the mean.
What is the probability of an event that will NEVER occur?
0 or 0%
In recent years, it was found that teenagers between ages 13 - 17 send/receive an average of 1740 text messages per month with a standard deviation of 550 text messages.
What is the z-score for a teenager who sends/receives 2150 text messages per month?
0.745
What is the bell curve?
The shape a normal distribution table
How many sides does a circle have?
Zero
What does it mean if a z-score is positive?
The data value is above the mean.
What is the probability of an event that is CERTAIN to occur?
1 or 100%
In recent years, it was found that teenagers between ages 13 - 17 send/receive an average of 1740 text messages per month with a standard deviation of 550 text messages.
If a teenager has a z-score of 1.38, about how many text messages did he or she send/receive that month?
Double Jeopardy!!!
2499
What is normal distribution?
Double Jeopardy!!!
When data is spread out normal or like a bell curve. 50% of the data greater than the mean, 50% of the data less than the mean. Mean, Mode, and Median are Equal
What ended in 1969?
1968
What does it mean if a z-score is negative?
The data value is below the mean.
What is the probability of flipping a coin three times and it landing on a head?
Double Jeopardy!!!
1/8
The Virginia Cooperative Extension reports that the mean weight of yearling (1-yo) Angus cattle is 1150 lbs. with a standard deviation of 80 lbs.
What is the z-score for a cow weighing 980 lbs.?
-2.125
If a z score is .8 what does that tell us?
It is within one standard deviation of the mean
What has a head, a tail, but no body?
A coin
Define z-score in your own words.
Double Jeopardy
A z-score represents the number of standard deviations a data value is away from the mean.
Probability of rolling a 7 on a dice?
Impossible
The Virginia Cooperative Extension reports that the mean weight of yearling (1-yo) Angus cattle is 1150 lbs. with a standard deviation of 80 lbs.
Is a cow weighing 1340 unusual? Explain.
Yes. The z-score is more than 2 s.d. from the mean.
Can a z score be negative and it still be within one standard deviation?
Yes, negative and positive does not matter
If one ship can cross the atlantic in 7 days, how long will it take 6 ships?
7 days
Give the formula for calculating a z-score.
data set minus mean divided by standard deviation
Probability of picking a face card out of a regular deck? Simplify
3/13
Give the formula to determine the data value associated with a give z-score.
x = (z)(s.d.) + mean
If a factory throws out all products that have a z score of 1.1 or more what are they throwing out.
Everything that is outside of 1 standard deviation from the mean
What do you call an empty parrot cage?
Double Jeopardy
Polygon