Sampling and Estimation Flashcards
the set of rules used to select a sample
sampling plan
With _______, we select every kth member until we have a sample of the desired size.
systematic sampling
Any difference between the sample mean and the population mean is
called _______ .
sampling error
the average return in excess of the risk- free rate
divided by the standard deviation of returns
The Sharpe ratio
The ___________ allows us to make quite precise probability statements
about the population mean by using the sample mean, whatever the distribution of
the population (so long as it has finite variance), because the sample mean follows
an approximate normal distribution for large- size samples.
central limit theorem
The formulas that we
use to compute the sample mean and all the other sample statistics are examples of
estimation formulas or __________.
estimators
To take the example of the mean, the calculated value of the sample mean in a given sample, used as an estimate of the population mean, is called a _________ of the population mean.
point estimate
An ________ estimator is one whose expected
value (the mean of its sampling distribution) equals the parameter it is intended
to estimate.
unbiased
An unbiased estimator is _______ if no other unbiased estimator of the same parameter has a sampling distribution with smaller
variance.
efficient
A _______ estimator is one for which the probability of estimates close to the value of the population parameter increases as
sample size increases.
consistent
A ___________ is a range for which one can assert with a given probability 1 − α, called the ____________, that it will contain the parameter it is intended to estimate. This interval is often referred to as the 100(1 − α)% confidence interval for the parameter
confidence interval, degree of confidence
_________ relates to overuse of the same or related data.
Data mining
When data availability
leads to certain assets being excluded from the analysis, we call the resulting problem ____________.
sample selection bias
A test design is subject to ______________ if it uses information that was not available on the test date.
look- ahead bias
A test design is subject to __________ if it is based on a time period that may
make the results time- period specific.
time- period bias
The standard deviation or standard error of the sample mean is
σ/srq(n)
A For a 99 percent confidence interval, the reliability factor we use with the t-distribution is
0.005
In tests concerning the variance of a single, normally distributed population, the test statistic is _________
chi-square (χ2) with n − 1 degrees of freedom, where n is sample size.
Test for equality of variances of two normally distributed populations.
F-statistic
The F-statistic is defined by the numerator and denominator degrees of freedom. The numerator degrees of freedom (number of observations in the sample minus 1) is the divisor used in calculating the sample variance in the numerator. The denominator degrees of freedom (number of observations in the sample minus 1) is the divisor used in calculating the sample variance in the denominator. In forming an F-test, a convention is to use the larger of the two ratios, as the actual test statistic.
Type I error
False negative
Type II error
False positive
The value of a test statistic is best described as the basis for deciding whether to:
A reject the null hypothesis.
B accept the null hypothesis.
C reject the alternative hypothesis
A
When samples are dependent, a ________________ is appropriate to conduct tests of the differences in dependent
items.
paired
comparisons test
A pooled estimator is used when testing a hypothesis concerning the:
A equality of the variances of two normally distributed populations.
B difference between the means of two at least approximately normally distributed populations with unknown but assumed equal variances.
C difference between the means of two at least approximately normally distributed populations with unknown and assumed unequal variances
B
The smaller the p-value, the ______ the evidence is against the null
hypothesis and in favor of the alternative hypothesis.
stronger
