Unit 4 - Normal Model Flashcards
Empirical Rule: How much of the area under the curve is between 1 and -1 standard deviations of the mean?
Empirical Rule: How much of the area under the curve is between 3 and -3 standard deviations from the mean?
Empirical Rule: How much of the area under the curve is between 2 and -2 standard deviations from the mean?
Describe a normal model
Bell-shaped, unimodal, symmetrical
Z Score Formula
Which distribution has the smallest mean?
Distribution A because its mean is -2. All the other distributions have a mean of 0.
Which distribution has the largest standard deviation?
Distribution D because it has the largest spread.
Which distribution has the largest sample size?
It cannot be determined.
A normal distribution shows us 100% of the population, but it does not show us the actual size of the population.
Which distribution has the smallest standard deviation?
Distribtuion B because it is the skinniest.
The histogram shown is approximately normal. Estimate the mean and standard deviation.
Mean = 10
Standard Deviation = approx 2
The histogram below is approximately normal. Estimate the mean and standard deviation.
Mean = 11
Standard Deviation = approx 3
A researcher is collecting data on the weights of female chipmunks. A certain female chipmunk has a z score of -2.3. What does this mean?
The chipmunk’s weight is 2.3 standard deviations below the mean weight of female chipmunks.
Which tool on the calculator would you use to find the blue shaded area?
Normalcdf
Lower: -999999
Upper: 1.18
Mean = 0
S.D. = 1
How could you find the missing z score on the diagram?
InvNorm
area: .20
You have to put in .20 (not .80) because you always put in the area to the LEFT
