=population standard deviation
s=sample standard deviation p=population proportion
p^ sample population
TABLE A on PAGE 201 IN NOTES
x~N( , )
if X is capitalized then Z is capitalized
STAT 3011 Study Guide
October 12, 2015
1. Population and sample:
(a) Population: A collection of all units in interest.
(b) Subject: An individual unit of a population.
(c) Sample: An observed subset of the units of a population.
a) The sample and population is 100 students at the school.
b) The main purpose of descriptive statistics is to reduce the data to simple summaries without
distorting or losing much information. Graphs and numbers such as percentages and
b) 4(0.20) + 3(0.40) + 2(0.30) + 1(0.10) = 2.7. This mean reflects what we expect for the long run
average of the observations.
b) The prob
a) My friends claim is wrong because all probabilities for the possible outcome must equal
one and there are only two possible outcomes in this instance making it a 0.5 probability
for heads and a 0.5 probability for tails. Also, he should run a large
We live in a world that is global, highly competitive, and
increasingly influenced by information technology, particularly the Internet. The first edition of our text Essentials
of Marketing Research became a premier source for new
This means that the probability that the profit is equal or less than $50,000 is 0.30
c. Mean of probability =80,000x0.70+50,000x0.20+20,0
STATS HW 2
a. Sample space: (Ben Carson, Bernie Sanders, Donald Trump,
Hillary Clinton, Marco Rubio, Ted Cruz, Other)
Conservative Liberal Moderate
HW 1 Savannah Johnson
a. Flipping the coin 500 times and observing all heads would be
more surprising than flipping a coin 5 times and observing all
heads. This is because when the sample size increases, the
prediction becomes more reliable.
b. I wou
a. x = number of years of education for self-employed individuals in the US
The sampling distribution of the sample mean for n=100 has a mean of 13.6.
Its standard error equals
The mean and standard deviation of the
a. Let the proportion of votes for a candidate in an election b p=.548
The point estimate represents a single value used to guess the parameter. Here, the
sample proportion pp is used to estimate p. Therefore, the point estimate
The mean IQ of all students at Lake Wobegon High School is larger than 100.
The alternative hypothesis states that the parameter falls in some alternative
range of values. Here the statement shows that the parameter, mean IQ of all
Finding probabilities for the standard normal distribution Z N ( 0,1 ) :
Using the z-table
Look for the probability that corresponds to the z-score of z* in the table.
P ( Z < z)
P ( Z > z)
Rewrite the expression as 1P ( Z < z ) , and then look for P ( Z