HDFS 2040 quiz questions

An alpha level of .01 indicates:

There is a 1% chance of a Type I error

When we use the standard error instead of the standard deviation:

We reduce variability in our measurements which increases reliability and gives us the best chance for increasing validity

What is the relationship between variance and reliability?

When variance is large than reliability is low

A researcher conducts a literature search and finds that women are better at detecting non-verbal communication than men. The researcher would like to replicate the study. What would be the researcher's null hypothesis?

Women are worse or no different than men at non-verbal communication detection

The SAT is used by universities to evaluate undergraduate applicants. An applicant's score was converted to a z-score for the admissions pocess. The applicant's z-score is 1.33. The student would be categorized as:

above average

The contents of cereal boxes have an average weight of 12 ounces with a standard deviation of .05 ounces. You decide to weigh the cereal box in your pantry and find that it weighs 12.01 ounces. How would you categorize the cereal box?

average

When determining the difference between standard deviation and standard errors; we use standard deviations to ___________ and standard errors to _____________.

compare individual values to a population; compare sample means to a population

paired sample t-tests are preferrd to indepenent sample t-tests becuase paired sample t-tests:

decrease variability which increases reliability which may increase validity

paired-sample t-tests are preferred to independent sample t-tests because paired sample t-tests:

decrease variability which increases reliability which may increase validity

The contents of cereal boxes have an average weight of 12 ounces with a standard weight of 12 ounces with a standard deviation of .05 ounces. You decide to weight the cereal box in your pantry and find that it weights 12.12 ounces. How would you categporize the cereal box?

extremely above average

Sitipanicic, Nolin, Fortin and Gobeil (2008) want to compare the IQ scores in a sample of 11 children with shaken baby syndrome to 11 children without the syndrome at an alpha of .05. Which statistical test should they use?

independent sample t-test

assigning numbers to the brands of cereal would be what type of variable

nominal

A psychologist wants to know whether wives and husbands who both serve in a foreign war gave similar levels of satisfaction in their marriage. To test this hypothesis, six married couples currently serving in Afghanistan were asked how satisfied that are with their spouse in a -point scale (7=very satisfied). Which statistical test should the psychologist use?

paired sample t-test

A psychologist wants to know whether wives and husbands who both serve in a foreign war gave similar levels of satisfaction in their marriage. To test this hypothesis, six married couples currently serving in Afghanistan were asked how satisfied that are with their spouse in a -point scale (7=very satisfied). Which population distribution should the researchers use?

population distribution of mean differences

A psychologist wants to know whether wives and husbands who both serve in a foreign war have similar levels of satisfaction in their marriage. To test this hypothesis, six married couples currently serving in Afghanistan were asked how satisfied they are with their spouse in a 7 point scale (7=very satisfied). Which population distribution should the researchers use?

population distribution of mean differences

Lopata, Hamm, Volker, and Sowinski (2007) are interested in studying the general motor and visual skills of children with a neurological development disorder. They give forty children with the disorder a test of motor proficiency where higher scores indicate better skills. The general normative population scores on average is a 50 on this test. Which population distribution should the researchers use?

population distribution of means

A college administrator states that the average high school GPA for incoming freshman students is normally distributed with a mean equal to 3.30 with a standard deviation of 0.20. Which statistical procedure would the college administrator use if he or she wanted to compare Jessica to all incoming freshman? Which population distribution should the researchers use?

population distribution of scores

A college administrator states that the average high school GPA for incoming freshman students is normally distributed with a mean equal to 3.30 with a standard deviation of 0.20. Which statistical proceudre would the college administrator use if he or she wanted to comaore Jessica to all incoming freshman? Which population distribution should the researchers use?

population distribution of scores

A resturant owner is considering moving his restaurant to a location next to a university. He would like to know if students eat out more often than the general population. The owner surveys 75 students on campus and finds that they eat out on average 12 times a week. Recent census data demonstrates the average person eats out 8 times a week. The dependent variable is:

ratio

Susan uses an observational measure children's behavior that is high in reliability. What can she conclude about the measure?

she doesn't know the validity of the meaure

A researcher wants to know whether perceived life satisfaction for older adults is rated differently than the overall population. The population life satisfaction score has been normed with a mean of 56.7 and a standard deviation of 9.2. The researcher collects data from a sample 50 adults at the local care home. Which statistical method should the researcher use to analyze the data?

single sample z-test

A rental car company claims the mean time to rent a car on their website is 60 seconds. A sample of 36 customers who attempted to rent a car on the website had a rent time of 75 seconds. What type of statistic should be used to test the claim at an alpha level of .05?

t-test

The formula for calculating a z-statistic is:

z = (M - µM)/ σM

A college administrator states that the average high school GPA for incoming freshman students is normally distributed with a mean equal to 3.30 with a standard deviation of 0.20. Which statistical procedure would the college administrator use if he or she wanted to compare Jessica to all imcoming freshman? Which statistical test should they use?

z-scores

A researcher theorizes that first-born children are more intelligent than other children. IQ is normed at an average of 100 with a standard deviation of 15. The researcher obtains a sample of 50 first-born children who have an average IQ of 105. What type of statistic should be used to test the claim at an alpha level of .05?

z-test

The average number of hours spent in a computerlab for stuudentd in the STATS 2010 course is 6.2 visits with a standard deviation of 0.9. Jessica spends 7.2 hours in the lab last week. What is her percentile?

87th

When conducting hypothesis tests, the population descriptions includes all of the following except:

A difference statement

Nick needs to estimate the variability of a population from a sample; however he does not know why he is using the degrees of freedom (N-1) in his formula. Provide an explanation for Nick.

A population distribution is infinite; however a sample distribution is not. By subtracting the finite or set number in a sample, the remaining numbers are free to vary infinitely. Hence degrees of freedom is N-1.

The SAT is used by universities to evaluate undergraduate applicants. An applicant's score was converted to a z-score for the admissions process. The applicant's z-score is -1.86. This student would be categorized as:

Below average

Sitipanicic, Nolin, Fortin and Gobeil (2008) want to compare the IQ scores in a sample of 11 children with shaken baby syndrome to 11 children without the syndrome at an alpha of .05. Which population distribution should the researchers use.

Population distribution of differences between means

When we have sample data, we must:

Re-calculate the standard deviation but not the mean for a population distribution of means

A false negative is related to:

Reject the null hypothesis

Although it has been said that students who sit in the front of the classroom tend to get better grades, there isn't any conclusive research to confirm the hypothesis. Dr. Jones decides to test the hypothesis by comparing the exam scores of ten students who always sit in the front row of the classroom to the overall exam scores of the class. The mean for the 10 students was 85% with a standard deviation of 5%. The class average was 80% with a standard deviation of 7%. At an alpha of .05, what is the statistical decision?

Reject the null hypothesis

A researcher is investigating the parenting styles of incarcerated fathers. There is no previous research that is conclusive on the topic. What would be the corresponding critical values if the researcher used an alpha of .10?

+/- 1.65

Alfred wants to use a t-test with a 5% Type 1 error rate for his study. Based on previous research findings, he expects the sample mean to be less than the population mean. He collects data from 27 participants. What critical value should he use?

-1.71

A researcher conducts a literature search and finds that women are better at detecting non-verbal communication than men. The researcher would like to replicate the study using an alpha level of 0.01. What would be the corresponding critical value?

2.33

Edwardo uses a sample of 62 participants for his study. How many values can vary infinitely in his sample?

61

A researcher is investigating the parenting styles of incarcerated fathers. There is no previous research that is conclusive on the topic. What would be the statistical decision if the researcher obtained a z-statistic of 1.50 and used an alpha of .10 when conducting his study?

Fail to reject the null hypothesis

The Auburn Junior High School would like to implement a healthy eating initiative that has been validated at many schools and has been shown to increase the consumption of fruits and vegetables. The junior high tests the new initiative on a group of students and obtains a z-statistic of 1.53. At an alpha level of 0.05, what would be the statistical decision?

Fail to reject the null hypothesis

The local juvenile detention center would like to implement a validated intervention that will decrease the aggression level in inmates. The detention center tests the intervention on 22 inmates. After 6 weeks, the number of aggressive incidents for the sample was 10 incidents lower than the total number of incidents at the center. If the population standard deviation is 30 incidents and the alpha level is 0.05, what would be the statistical decision?

Fail to reject the null hypothesis

Sammy is studying personality and uses a writing analysis measure that has been shown to be low in validity. What can Sammy conclude about the measure?

He doesn't know the reliability of the measure

All the following describe a hypothesis expect for:

Hypotheses are general questions based on individual experiences

The central limit theroem suggests all of the following expect

That "square" and "square root" functions are needed to correct for skewness on distribution of means

The central limit theorem suggests all of the following except:

That "square" and "square root" functions are needed to correct for skewness on distributions of means

The mean represents

The balancing point of the distribution

There are two assumptions that must be met in order to perform a z-test. They are:

The dependent variable must be scale and we must have the parameters for one of the populations

Greg is studying aggression by reviewing credit card statements. He finds that his measure is low in reliability. What can Greg conclude?

The measure is low in validity

All of the following are criteria for grading the tables you create for exams except for:

The middle intervals should not have a frequency count of zero

The symbol N represents

The number of observations in the dataset

When conducting hypothesis tests, the hypotheses statements includes all of the following except:

The procedures used to measure the variable

The symbol σ represents:

The standard deviation on a distribution of scores

The symbol σM represents:

The standard error on a distribution of means