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Test 2 Review
Vocabulary and symbolic notation:
 Point estimate of the population mean  of a statistic used to estimate the value
of a parameter.
 Confidence interval- is an interval of numbers obtained from a point estimate and
a percentage that specifies how confident we are that a parameter lies in an
interval.
 Confidence level-confidence percentage
 Margin of Error (E)
 T-distribution, degrees of freedom
Assumptions for Confidence Intervals:
 Point estimate of the population mean   value of a statistic used to estimate
the parameter.
 Normal populations or large samples.
 All samples are simple random samples
Chapter 6
Know the properties of the normal and standard normal curves
 Center at 
 Symmetry
 Area under the curve is 1
 Most area within 3 standard deviations about the mean
 Bell shaped
Know how to convert from a normal variable to a standard normal variable.
x-
z

Know the 68.26-99.54-99.74 Rule
Know how to find the areas under the standard normal and normal curve using tables
and using symmetry.
Know how to find x variable for a given probability or percentage.
Know how to construct a normal probability plot.
Know how to determine if data is normally distributed.
Chapter 7
 Know what is the sampling distribution of the sample mean X , know the mean
and standard deviation of X ,
 x and  x . Know how the shape of the
distribution changes with increasing sampling size n.
 When X has normal distribution, when approximately normal distribution. Know
the central limit theorem.
 Find probabilities using the sampling distribution of X .
Chapter 8
 Know that X is a point estimate of 
 Know how to compute (1   )  100% Confidence Interval for 
1. When  is known (Z-interval)
2. When  is unknown (T-interval)
 Interpret the Confidence Interval
 What is the margin of error for a given, CI, know how it changes with
increased sample size. Also know how the confidence level affects the
Confidence Interval.
 Estimate the sample size for given E and confidence level.
Chapter 9
Know new vocabulary and symbolic notation:
 Null and alternative hypotheses
 Two - tailed, left-tailed, right-tailed alternative hypothesis
 Type I and II errors