Blog

The five number summary for test scores (in points) was obtained from applicants who applied for a job is given by:   Min Q1 Med Q3 Max 42 48 50 52 60 Use the information from this five-number summary to identify the quantities listed below.

Researchers surveyed 50 students (group 1) sitting in the back half of the classroom and 15 students (group 2) sitting in the front half of the classroom and recorded their GPA.  The goal of the study was to see if, on average, the students that sat in the back half of the classroom have lower GPAs than those that sat in the front half. The sample statistic is -0.170 (using back minus front) with standard error 0.062.  The p-value is 0.032. Complete the statements below: Using a significance level of 0.05, the researchers should [answer1] the null hypothesis. It is possible that they have committed a type [answer2] error.

Researchers test the provided hypotheses about two variables: ‘Favorite type of Apple’ (Red Delicious, Granny Smith, Honeycrisp, Empire, Gala) and ‘Time Zone where you Live: ‘(Pacific, Mountain, Central, Eastern) when based on a sample of n = 200 U.S. adults. H0: There is no association between favorite type of apple and time zone where you live. Ha: There is an association between favorite type of apple and time zone where you live Assume the researchers calculated a p-value of 0.246.  What is the correct conclusion for this hypothesis test using a significance level of 0.05?

Does reintroducing wolves into an ecosystem improve the overall health of the system (as measured by species richness)? A team of ecologists tested this on 30 different forested parks. Assume the researchers performed an experiment and calculated a p-value of 0.019.  Complete the statements below: Using a significance level of 0.05, the researchers should [answer1] the null hypothesis. It is possible that they have committed a type [answer2] error.

The hypotheses for a test for a population proportion are H0: p = 0.70 versus Ha: p ≠ 0.70. A sample of 100 is used with the hypothesis test If the test statistic equals 2.82, which correctly represents how the p-value would be calculated? [answer1] of 2.82 on a [answer2].

The figure below displays four different normal distributions.   Match the lines above to the correct parameters found with each normal distribution Orange (dashes and dots): N(

Many drivers of cars that can run on regular gas instead buy premium gas in the belief that they will get better gas mileage (miles per gallon). To test that belief, a sample of 10 cars was obtained from a company fleet where all the cars can run on regular gas. Each car is filled first with either regular or premium gasoline, as decided by a coin toss, and the mileage for that full tank of gas is recorded. The mileage is again recorded for the same cars with a full tank of gas of the other kind of gasoline. The car drivers were unaware that they were participating in an experiment. Research Question: Does the data suggest, on the average, that the cars had a higher gas mileage (in miles per gallon) with premium gas when compared to regular gas? This is an example of paired data because there are two recorded measurements for each [answer1].  On the average, 2.0 [answer2] miles per gallon was achieved with regular gas.  When using the paired t procedure, we [answer3] successful in reducing variation between the types of gasoline, because the standard deviation for the differences: sd = [answer4] miles per gallon is [answer5] the standard deviations found with the original two samples for Premium and Regular gas.

A randomly selected sample of n = 20 activity monitor/ tracker users completed a survey. These activity monitor/ tracker users indicated that they walked on average 8,000 steps per day with a standard deviation of 90 steps per day. The calculated standard error of the mean is 20.1 steps per day. Assume that all conditions are met to use the theoretical t distribution for inference.  Which is correct 98% confidence interval for the average number of steps walked per day by activity monitor/tracker users?

Many drivers of cars that can run on regular gas instead buy premium gas in the belief that they will get better gas mileage (miles per gallon). To test that belief, a sample of 10 cars was obtained from a company fleet where all the cars can run on regular gas. Each car is filled first with either regular or premium gasoline, as decided by a coin toss, and the mileage for that full tank of gas is recorded. The mileage is again recorded for the same cars with full tank of gas of the other kind of gasoline. The car drivers were unaware that they were participating in an experiment. Research Question: Does the data suggest, on the average, that cars had a higher gas mileage (in miles per gallon) with premium gas  when compared to regular gas? This is an example of paired data because there are two recorded measurements for each [answer1].  On the average, 2.0 [answer2] miles per gallon was achieved with premium gas.  When using the paired t procedure, we [answer3] successful in reducing variation between the types of gasoline, because the standard deviation for the differences: sd = [answer4] miles per gallon is [answer5] the standard deviations found with the original two samples for Premium and Regular gas.

A researcher uses a sample of 140 Labrador service dogs in training to conduct a chi-square test for association between two variables: coat color (yellow, black, chocolate), and whether success was achieved with completion of the service dog training program  (yes, no).  After calculating the expected counts and summing the chi-square contributions, the chi-square statistic is equal to 3.01. Which figure below correctly shows the p-value for this test?