Chapter 1&2
What is the symbol for sample variance
s2
What is the mode?
The z values between -2 and -3 as well as between 2 and 3 are considered to be what type of values?
Unusual values
When the question is looking for the probability of finding an X value greater than the average what must we do?
Subtract from 1
The law of large numbers describes the relationship between sample means and the population mean as what number approaches infinity?
The number of trials
Age, test scores, or standard intelligence quotient (IQ) scores are all examples of which scale of measurement?
Interval
In a negatively skewed distribution. the mean would be found where compared to the median?
What is the mean for all z scores of a normal distribution?
What is P(Z<1.32)
0.9066
What is the formula for the standard error of the mean?
Sigma/sqrt(n)
1st, 2nd, and 3rd place is an example of which scale of measurement?
In a distribution with positive skew, scores with the highest frequency are found where?
A sample of n=500 scores is transformed into Z scores. The Standard deviation for the 500 Z scores is what?
1
What is P(-0.98<Z<1.78)?
0.799
In a normal distribution, the middle 50% is bound by what z values?
-0.67<Z<0.67
What is the sample size according to the frequencies table below?
X f
5 0
6 10
7 5
8 1
9 4
10 2
22
What is the sum of squares according to the frequencies table below?
X f
5 0
6 10
7 5
8 1
9 4
10 2
87.35
For a population that has mu=80 and sigma=8, what is the X value corresponding to Z=0.60
84.8
The average ACT composite score is 21 with a standard deviation of 2.3. What ACT scores separate the middle 60%.
19.07 and 22.93
or
19 and 23
High schoolers drink on average 64 oz every day with a standard deviation of 6.19 What is the probability of selecting 15 students that drink less than 60 oz of water a day?
0.006
What is the mean according to the frequencies table below?
X f
5 0
6 10
7 5
8 1
9 4
10 2
7.23
What is the standard deviation according to the frequencies table below?
X f
5 0
6 10
7 5
8 1
9 4
10 2
2.04
For a population mu=100 and sigma=5.5, what is the corresponding Z value if our X value is equal to 95?
0.91
The average height for the adult female is 66 inches with a standard deviation of 2.5. What proportion of females have a height between 63 and 69 inches?
0.7698
John just bought a limo. The limo has a weight capacity of 1,550 pounds. The limo has seven seats and a driver. Men have an average weight of 188.3 pounds with a standard deviation on 8.3. Women have an average weight of 170.8 pounds with a standard deviation of 3.2. What is the highest probability of the limo being overloaded?
0.0314