5-1
Sampling and Sampling
Distributions
5-2
Inference Process
Estimates
& tests
Sample
statistic
(X )
Population
Sample
5-3
Using Statistics
Statistical Inference:
Predict and forecast values of
population parameters.
Test hypotheses about values of
po
The Normal Distribution
Probability distributions
We
use probability
distributions because
they work they fit lots
of data in real world
100
80
60
40
20
Std. Dev = 14.76
Mean = 35.3
N = 713.00
0
Ht (cm 1996
)
Height (cm) of Hypericum cumulicola at Archbo
Introduction to
Probability
AMIT K BARDHAN
FA C U LT Y O F M A N A G E M E N T S T U D I E S
UNIVERSITY OF DELHI
[email protected]
1
The prospect of getting rich is highly motivating, and
few people get rich without taking a gamble.
Peter L. Bernstein
TESTING HYPOTHESES
(ONE-SAMPLE TEST)
Chapter Topics
Research Hypothesis
a statement of what the researcher
believes will be the outcome of an
experiment or a study.
Statistical Hypotheses
a more formal structure derived from the
research hypothesis.
What
Linear correlation and
linear regression
Covariance
n
(x
i
cov ( x , y )
X )( yi Y )
i
1
n 1
Interpreting Covariance
cov(X,Y) > 0
X and Y are positively correlated
cov(X,Y) < 0
X and Y are inversely correlated
cov(X,Y) = 0
X and Y are independent
Corre
Questions
Confidence Intervals
A point estimate consists of a single
sample statistic that is used to estimate the
true population parameter.
TRUE / FALSE
The sample mean is a point estimate of
the population mean.
TRUE / FALSE
A point estimate consist
Questions
Sampling and Estimation
1. A company selling apparel online sends out emails every
Monday to all its customers who made a purchase. This is
an example of a
A) systematic sample.
B) convenience sample.
C) simple random sample.
D) stratified sampl
Question 1:
In its standardized form, the normal distribution
A) has a mean of 0 and a standard deviation
of 1.
B) has a mean of 1 and a variance of 0.
C) has an area equal to 0.5.
D) cannot be used to approximate discrete
probability distributions.
Quest