IB Bio Stats Practice

What does the following scatter plot show?

• No correlation between these variables
• Strong positive correlation between these variables 
• Strong negative correlation between these variables
• Weak negative correlation between these variables

Researchers at a pharmaceutical company tested a new sunscreen formula. They applied the new formula to one arm and the old formula to the other arm of each of a set of individuals, randomly choosing the arms for each formula. Which type of test could they use to determine if there was a significant difference in the effectiveness of the sunscreens?

• Chi-Squared

• t-test

• ANOVA

• r squared

Researchers at a pharmaceutical company tested a new sunscreen formula. They applied the new formula to one arm and the old formula to the other arm of each of a set of 15 individuals, randomly choosing the arms for each formula. How many degrees of freedom are there for a t-test?

• 14

• 29

• 28

• 13

A dairy scientist compared milk production of cows fed 4 diets. He randomly divided a set of 120 cows into four groups. Each group was fed a different diet for one month. What type of statistical test could determine if there is a significant difference between the variances of all 4 groups?

• t-test

• chi-squared

• ANOVA

• r squared

The National Park Service compared the average amount of money spent by visitors in two different national parks.

The minimum value spent was $0, while the maximum value spent was $100. What was the mean value spent?

• $95

• $50

• Not enough information

• $68

A data set contains the following values:

5, 9, 10, 10, 11, 3, 5, 20, 1

The mean value is 8.22

What value is closest to the standard deviation?

• 68%

• 3.5

• 9.5

• 95%

Tags

NGSS.HS-LS3-3

To study the change in attitude towards statistics over the course of the semester, a professor selected a simple random sample of 48 students. She administered a questionnaire to the students at the beginning and again at the end of the semester. Which of the following is a null hypothesis for this experiment?

• The students at the end of the semester enjoy statistics more than they did at the start of the semester.

• There is no difference between individual students at the end of the semster

• There is no significant difference between the mean enjoyment of students at the start or end of the semester.

• There is a significant difference between students who enjoyed and students who did not enjoy statistics.

Tags

NGSS.HS-LS3-3

What does the size of the standard deviation indicate about data? 

• How accurately the data were measured
• How widely the data are spread above and below the mean 
• Whether the mean is larger or smaller than it should be
• Whether the reliability of the data is greater or less than 68%

Does exercise cause a significant increase in prolactin release?

• yes, because error bars overlap in the T=1 hr means

• no, because error bars overlap in the T=1 hr means

• yes, because there is more prolactin released after exercise

• no, because the error bars in the with exercise overlap

An ANOVA test between the growth rates of several different species of plants reveals a F value of around 15 and an approximate p value of .000007. What action should the researchers take with this result?

• Accept the null hypothesis

• Reject the null hypothesis

• More information is needed