Chapter 1&2
What is the symbol for sample standard deviation
s
What is the relationship between variance and standard deviation?
Standard deviation is the square root of variance
The z values between -2 and +2 are considered to be what type of values?
Ordinary values
When the question is looking for the probability of finding and X value greater than the average?
Subtract from 1
What is the term that is defined as the standard deviation of all sample means?
Standard error of the mean
Nominal
What is the mode?
The value with the highest frequency in the distribution.
What is the mean for all z scores of a normal distribution?
0
What is P(Z>1.9)?
0.0287
What is the formula for the standard error of the mean?
Sigma/sqrt(n)
Travel speed is measured by distance traveled divided by time traveled. This is an example of which scale of measurement?
Ratio
Mean is an appropriate statistical measure for central tendency for what two scales of measurement?
Interval and Ratio
What is the range for probability
0<P<1
What is P(-1.36<Z<2.78)?
0.9104
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
1 3
2 7
3 5
4 1
5 10
6 4
30
What is the sum of squares according to the frequencies table below?
X f
1 3
2 7
3 5
4 1
5 10
6 4
82.7
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 23 with a standard deviation of 2.9. What ACT score separates the top 25% from the rest?
24.9 or 25
Newborn babies drink on average 5 oz of milk per feeding with a standard deviation of 1.23. What is the probability of selecting 15 babies that drink less than 4.7 oz of milk per feeding?
0.1736 or 17.36%
What is the mean according to the frequency table below?
X f
1 3
2 7
3 5
4 1
5 10
6 4
3.67
What is the standard deviation according to the frequencies table below?
X f
1 3
2 7
3 5
4 1
5 10
6 4
1.69
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 water taxi. The water taxi has a weight capacity of 18,250 pounds. The water taxi has 75 seats and a driver. Each passenger is able to bring one 50 pound suitcase. 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 water taxi being overloaded?
0.0044 = 0.44%