Introduction to statistics

1.

A scientist is conducting a study on the effect of eating chocolate and overall mood. They believe that gender is a significant factor.  The participants are divided by gender.  Then, within each group, participants are randomly assigned to consume either chocolate or a placebo and then rate their mood for the day. This experiment will run for two weeks. 

Which type of experimental design does this situation describe?

2.

To compare the teaching methodologies of two of its eighth-grade math teachers, a school decides to compare student test scores from the two classes throughout the year.

Which type of statistical study is the school conducting?

3.

Peter randomly draws a card from a deck of 24. The odds in favor of his drawing a spade from the cards are 1:3.

What is the probability ratio for Peter to draw a spade?

4.

Select the correct statement regarding experiments. 

A researcher can carefully control the explanatory variables and observe human responses.

5.

A trainer is studying the effects of vitamin D on his athletes. He has realized that there are many potential confounding factors, such as gender and age. To limit the effect of these confounding variables, he decided to first group two athletes together based on these variables (for example, two 21-year-old males). Then he randomly assigned one person to receive the vitamin D and the other to receive a sugar pill. 

What type of experimental design does this situation demonstrate? 

6.

Amanda is the owner of a small chain of dental offices. She sent out the yearly satisfaction survey to 600 randomly selected patients and received 544 surveys back. When looking through the results, she noticed that the downtown dental office staff had 84% of clients reporting satisfaction with services, while the uptown dental office staff had 76% of clients reporting satisfaction with services.  

Which of the following sets shows Amanda's null hypothesis and alternative hypothesis?

7.

Which of these statements best defines a stratified random sample?

8.

What is the probability of drawing a red card or a queen from a standard deck of 52 cards?

9

Ryan is playing a multiplication game with a pile of 26 cards, each with a number on them. Each turn, he flips over two of the cards, and has to multiply the numbers.

How many possible outcomes are there on Ryan's first turn flipping two cards?

10.

The average number of road accidents that occur on a particular stretch of road during a month is 7. 

What is the probability of observing exactly three accidents on this stretch of road next month?