CCJS 200 Exam 1 – Fundamentals of Criminological
Statistics
If I wanted to know the average reading level of prison inmates in the United States, and I
studied this by giving a reading comprehension test to 700 inmates whom I've selected from
across the U.S., what would be my population and what would be my sample? - correct answer
✔✔Population = The average reading level of all U.S. prison inmates
Sample = 700 inmates
If the actual reading level of all prison inmates in the U.S. is the 9.2nd grade, and the reading
level of the 700 inmates I've selected and studied is the 9.6th grade, then the 9.2nd grade is my
______________ (population parameter or sample statistic) while the 9.6th grade is my
____________(population parameter or sample statistic). - correct answer ✔✔9.2nd grade is
population parameter
9.6th grade is sample statistic
What is the relationship between my sample statistic and my population parameter? - correct
answer ✔✔Use sample statistic to make an inference about the unknown population value. We
usually will not know the value of the population parameter. We take a sample from the
population in order to get an estimate as to what that population parameter might be.
Is my population parameter known or unknown? Is it knowable? - correct answer ✔✔Usually it
is unknown and is knowable
When I take a sample from a population, will the sample statistic be equal to the population
parameter? Why or why not? If I took a second sample will that sample statistic be equal to the
first sample statistic? What is this called? - correct answer ✔✔The sample statistic will almost
never be the exact value of the population parameter because we only have a small proportion
of the population in our sample. If we took a second sample and calculated a sample statistic it
would not likely be equal to the first sample statistic because we would have different elements
, in this sample than the first. This is called sample to sample variability or sampling error.
Sampling error is the price we pay for taking a sample and not studying the entire population.
If the sample statistic is not equal to the population parameter, what can I do to ensure that
they are close? In other words, how can I increase the precision or accuracy of my sample
statistic? - correct answer ✔✔In order to increase the precision of my sample statistic (that is, in
order to reduce sample to sample variability or sampling error) I can do two things: (a) take a
larger rather than a smaller sample, (b) take a probability rather than a non-probability sample.
If I take a sample of 700 prison inmates, and all I want to know about them is the average
reading level of this group of 700, am I using descriptive or inferential statistics? - correct
answer ✔✔If I take a sample of 700 prison inmates and gave them a reading comprehension
test and all I wanted was to know the average reading level of these 700, then I would be using
descriptive statistics - a mean.
If I take a sample of 700 prison inmates and I want to know their reading level so that I can say
something about the reading level of prison inmates in the entire United States, am I using
descriptive or inferential statistics? - correct answer ✔✔If it took a sample of 700 prison
inmates and gave them a reading comprehension test and I wanted this information in order to
estimate what the reading level was of all U.S. prison inmates then I would be using inferential
statistics - again, a mean. In this case, however, I would be using my mean not to describe the
reading level of my 700 inmates, but to make an inference about an unknown population
parameter - the average reading level of all U.S. prison inmates.
If I want to make an inference from a sample statistic to an unknown population parameter,
should I use a non-probability or a probability sample? - correct answer ✔✔If you use a sample
statistic to make an inference about an unknown population parameter then a probability
sample is better than a non-probability sample because it will allow you to make your estimate
more precise and reduce sampling error.
The symbol or term for a population parameter for a mean is ______ and the symbol or term
for the corresponding sample statistic is ________________. - correct answer ✔✔The symbol
for an unknown population mean is μ while the symbol for the sample statistic is .
Statistics
If I wanted to know the average reading level of prison inmates in the United States, and I
studied this by giving a reading comprehension test to 700 inmates whom I've selected from
across the U.S., what would be my population and what would be my sample? - correct answer
✔✔Population = The average reading level of all U.S. prison inmates
Sample = 700 inmates
If the actual reading level of all prison inmates in the U.S. is the 9.2nd grade, and the reading
level of the 700 inmates I've selected and studied is the 9.6th grade, then the 9.2nd grade is my
______________ (population parameter or sample statistic) while the 9.6th grade is my
____________(population parameter or sample statistic). - correct answer ✔✔9.2nd grade is
population parameter
9.6th grade is sample statistic
What is the relationship between my sample statistic and my population parameter? - correct
answer ✔✔Use sample statistic to make an inference about the unknown population value. We
usually will not know the value of the population parameter. We take a sample from the
population in order to get an estimate as to what that population parameter might be.
Is my population parameter known or unknown? Is it knowable? - correct answer ✔✔Usually it
is unknown and is knowable
When I take a sample from a population, will the sample statistic be equal to the population
parameter? Why or why not? If I took a second sample will that sample statistic be equal to the
first sample statistic? What is this called? - correct answer ✔✔The sample statistic will almost
never be the exact value of the population parameter because we only have a small proportion
of the population in our sample. If we took a second sample and calculated a sample statistic it
would not likely be equal to the first sample statistic because we would have different elements
, in this sample than the first. This is called sample to sample variability or sampling error.
Sampling error is the price we pay for taking a sample and not studying the entire population.
If the sample statistic is not equal to the population parameter, what can I do to ensure that
they are close? In other words, how can I increase the precision or accuracy of my sample
statistic? - correct answer ✔✔In order to increase the precision of my sample statistic (that is, in
order to reduce sample to sample variability or sampling error) I can do two things: (a) take a
larger rather than a smaller sample, (b) take a probability rather than a non-probability sample.
If I take a sample of 700 prison inmates, and all I want to know about them is the average
reading level of this group of 700, am I using descriptive or inferential statistics? - correct
answer ✔✔If I take a sample of 700 prison inmates and gave them a reading comprehension
test and all I wanted was to know the average reading level of these 700, then I would be using
descriptive statistics - a mean.
If I take a sample of 700 prison inmates and I want to know their reading level so that I can say
something about the reading level of prison inmates in the entire United States, am I using
descriptive or inferential statistics? - correct answer ✔✔If it took a sample of 700 prison
inmates and gave them a reading comprehension test and I wanted this information in order to
estimate what the reading level was of all U.S. prison inmates then I would be using inferential
statistics - again, a mean. In this case, however, I would be using my mean not to describe the
reading level of my 700 inmates, but to make an inference about an unknown population
parameter - the average reading level of all U.S. prison inmates.
If I want to make an inference from a sample statistic to an unknown population parameter,
should I use a non-probability or a probability sample? - correct answer ✔✔If you use a sample
statistic to make an inference about an unknown population parameter then a probability
sample is better than a non-probability sample because it will allow you to make your estimate
more precise and reduce sampling error.
The symbol or term for a population parameter for a mean is ______ and the symbol or term
for the corresponding sample statistic is ________________. - correct answer ✔✔The symbol
for an unknown population mean is μ while the symbol for the sample statistic is .
