Download April Renee Canales Reading Assignment 3 Topics 43

April Renee Canales
Reading Assignment 3
Topics 43-50
Topic 43
1. Which branch of statistics (“inferential” or “descriptive”) helps researchers to
summarize data so they can be easily comprehended?
Descriptive statistics summarize data so they can easily be comprehended.
2. According to Table 1 in this topic, how many participants had a score of 19?
A total of 9 participants had a score of 19.
3. What is the name of the statistic that describes how many participants per 100 have
a certain characteristic?
Percentages describe how many participants per 100 have a certain characteristic.
4. Which branch of statistics helps researchers to draw inferences about the effects of
sampling errors on their results?
Inferential statistics help researchers draw inferences about the effects of sampling
errors on the results that are described with descriptive statistics.
5. If a researcher tests a random sample instead of all members of a population, is it
likely that the sample results will be the same as the results the researcher would
have obtained by testing the population?
No because random sampling produces errors that statisticians call sampling errors.
6. Is a margin of error a “descriptive” or an “inferential” statistics?
Margin of error is an inferential statistic.
7. Are significance tests associated with “descriptive” or “inferential” statistics?
Significance tests are associated with inferential statistics.
8. By studying populations, do researchers obtain “statistics “ or “parameters”?
Studying populations researchers obtain parameters.
9. By studying samples, do researchers obtain “statistics” or “parameters”?
Studying samples researchers obtain statistics.
Topics 44
1. How many explanations were there for the difference between psychologists and
engineers in the example in this topic?
There were three possible explanations for the difference between psychologists
and engineers in the example.
2. What does the null hypothesis say about sampling error?
The null hypothesis says the observed difference in a study is created by sampling
error, which refers to random errors.
3. Does the term sampling error refer to “random errors” or to “bias”?
The term sampling error refers to random errors.
4. The null hypothesis says the true difference equals what numerical value?
The null hypothesis says the true difference equals zero.
5. Significance tests are designed to determine the probabilities regarding the truth of
what hypothesis?
Significance tests are designed to determine the probabilities regarding the truth of
the null hypothesis.
6. The expression p < .05 stands for what words?
The probability that the null hypothesis is a correct hypothesis is less than 5 in 100.
7. Do researchers reject the null hypothesis when the probability of its truth is “high”
or when the probability is “low”?
Researchers reject the null hypothesis when the probability of its truth is low.
8. What do researchers do if the probability is greater than .05?
Researchers fail to reject the null hypothesis.
9. What is an alternative way of saying a researcher has rejected the null hypothesis?
An alternative way of saying a researcher has rejected the null hypothesis is to state
that the difference is statistically significant.
10. Are null hypotheses more likely to be explicitly stated in a “journal article” or in a
“dissertation”?
It is more common to find the null hypotheses stated in dissertations.
Topic 45
1. If a researcher asks participants to name the country in which they were born, the
researcher is using which scale of measurement?
If the researcher asks participants to name something, they are using nominal
scales.
2. Which two scales of measurement have equal distances among the scores they
yield?
Measurements at the interval and ratio levels have equal distances among the
scores they yield.
3. If a researcher assigns a teacher to rank students according to their oral-language
skills, the researchers is using which scale of measurement?
If the researcher ranks students according to their oral language skills, the
researcher is using ordinal scale of measurement.
4. Which scale of measurement has an absolute zero?
The ratio scale has an absolute zero point.
5. Which scale of measurement is at the lowest level?
The lowest level scale is called the nominal level or nominal scale.
6. Objective, multiple-choice achievement tests are usually assumed to measure at
what level?
Objective, multiple-choice achievement tests are usually assumed to measure
interval scales.
7. If a researcher measures in such a way that he or she finds out which participants is
more honest, which is the next most honest, and so on (without measuring to
determine how much honest each one has), the researchers is measuring with what
scale of measurement?
The researcher is measuring with an ordinal scale.
8. The number of minutes of overtime work that employees perform is an example of
which scale of measurement?
It is an example of a nominal scale of measurement.
9. Weight measured in pounds is an example of which scale of measurement?
Weight is an example of the ratio scale.
Topic 46
1. If 600 individuals in a population of 1,000 are Democrats, what is the corresponding
percentage of Democrats?
60% of the individuals are Democrats.
2. When reporting a percentage, is it a good idea to also report the underlying number
of cases?
Yes, it is desirable to also report the underlying numbers of cases.
3. Do researchers use “univariate” or “bivariate” analyses to examine relationships
between two nominal variables?
Researchers use bivariate analyses to examine relationships between two nominal
variables.
4. Percentages for different groups are expressed on a common scale with what base?
Percentages for different groups are expressed on a common scale with a base of
100.
5. What is the base for a proportion?
A proportion has a base of 1.
6. Are “percentages” or “proportions” easier for most individuals to comprehend?
Percentages are easier for most individuals to comprehend.
7. When consumers of research encounter proportions in research reports, it is a good
idea to do what?
It is a good idea to convert the proportions mentally into percentages.
Topic 47
1. When researchers study a sample are the results called the “true results” or the
“observed results”?
The results are called the observed results.
2. According to the null hypothesis, what created the difference in Table 1 in this
topic?
The difference in Table 1 in this topic was created by random sampling errors.
3. What is the name of the test of the null hypothesis used in this topic?
The name of the test of the null hypothesis used in the topic is called chi-square.
4. According to this topic, should the typical consumer try to interpret the value of df?
No, a typical consumer should not try to interpret the value of df.
5. What is the symbol for probability?
The symbol of probability is p.
6. If a researcher found that a chi-square test of a difference yielded a p of less than 5
in 100, on the basis of conventional wisdom, what should the researcher conclude
about the null hypothesis?
The researcher would reject the null hypothesis.
7. Does “p < .05” or “p > .05” usually lead a researcher to declare a difference
statistically significant?
A researcher usually declares a difference statistically significant using
p > .05.
8. If a researcher fails to reject a null hypothesis, is the difference in question
statistically significant?
No, the difference in question is statistically insignificant.
9. If a researcher has a statistically significant result, should the null hypothesis
remain on the list of viable explanations for an observed difference?
No, a researcher must have a statistically insignificant result to keep the null
hypothesis on the list of viable explanations for an observed difference.
Topic 48
1. Which type of analysis classifies participants in terms of two variables in order to
examine the relationship between the two variables?
Bivariate analysis classifies participants in terms of two variables in order to
examine the relationship between the two variables.
2. What decision should researchers make about the null hypothesis if a chi-square
test leads to the conclusion that the observed difference are unlikely to be due to
random errors?
The researcher should fail to reject the null hypothesis.
3. If p = .05 for a chi-square test, chances are how many in 100 that the null hypothesis
is true?
There are 5 chances in 100 that the null hypothesis is correct.
4. When a researcher uses the .01 level, what are the odds of making a Type I Error?
The odds of making this type of error are 1 in 100.
5. What is the name of the error researchers make when they fail to reject the null
hypothesis when, in fact, it is an incorrect hypothesis?
Type II Error occurs when a researcher fails to reject the null hypothesis when it
was in fact an incorrect hypothesis.
6. What is the name of the error researchers make when they reject the null
hypothesis when, in fact it is an incorrect hypothesis?
Type I Error occurs when a researcher rejects the null hypothesis when it was in
fact a correct hypothesis.
7. Why is random sampling desirable even though it creates errors?
Random sampling is desirable because it is free from bias.
Topic 49
1. According to Figure 1, about how many participants had a score of 16?
About 57 participants had a score of 16.
2. In Figure 1, are the frequencies on the “vertical” or the “horizontal” axis?
The frequencies are on the vertical axis.
3. What is the name of the curve that is symmetrical?
The name of the curve that is symmetrical is called a frequency polygon.
4. If a distribution has some extreme scores on the right (but not on the left), it is said
to have what type of skew?
It is said to have a positive skew.
5. If a distribution is skewed to the left, does it have a “positive” or a “negative” skew?
It is said to have a negative skew.
6. In most populations, income has what type of skew?
Income has a positive skew.
7. Does a distribution with a tail to the right have a “positive” or a “negative” skew?
It is said to have a positive skew.
Topic 50
1. Which average is defined as the most frequently occurring score?
The mode is defined as the most frequently occurring score.
2. Which average is defined as the balance point in a distribution?
The mean is defined as the balance point in a distribution.
3. Which average is defined as the middle score?
The median is defined as the middle score.
4. What is the formal definition of the mean?
The formal definition of the mean is the value around which the deviations sum to
zero.
5. How is the mean calculated?
Adding up the scores and dividing by the number of scores can calculate the mean.
6. Should the mean be used for highly skewed distributions?
No, the median is used when a distribution is highly skewed.
7. Should the median be used for highly skewed distributions?
Yes, the median should be used for highly skewed distributions.
8. Which one of the three averages is very seldom used in formal reports of research?
The mode is very seldom used in formal reports of research.
9. What is a synonym for the term averages?
A synonym for the term averages is measures of central tendency.