Research Methods KP #3

External validity matters most for which type of claim below?

• a) "Introverts have fewer friends than extroverts"

• b) "Getting a puppy makes people happier"

• c) "Half of all pet owners talk to their pets in a cutesy voice frequently"

• d) “Taking vitamin C when you have a cold shortens the length of the cold”

Researchers want to know what percentage of Americans plan to watch the Super Bowl this year. What is the best way for them to get a sample that represents the whole U.S. population?

• a) Survey a random sample of Americans

• b) Survey only football fans

• c) Survey a sample of people at the supermarket

• d) Survey their family and friends

A poll reports that 28% of Americans believe the government is covering up information about UFOs. The poll has a margin of error of +/- 5%. What can we conclude?

• a) Exactly 28% of Americans believe this

• b) If the poll was conducted 100 times, about 28% would believe this in 95 of those polls

• c) We can be 5% certain that 28% of Americans believe this

• d) Somewhere between 23-33% of Americans likely believe this

Having a representative sample matters most for which claim below?

• a) "Morning people are more productive at work."

• b) “Taking magnesium supplements reduces anxiety.”

• c) “35% of Americans own a smartwatch.”

• d) “People with high self-esteem have larger social circles.”

Dr. Lee is studying high schoolers' interest in STEM careers. There are 10 high schools in the district. She randomly selects 4 schools. From each she randomly surveys 200 students. What sampling technique did Dr. Lee use?

• a) Snowball sample

• b) Multistage sample

• c) Convenience sample

• d) Quota sample

Convenience sampling relies on:

• a) Surveying those easy to access

• b) Surveying all types of people

• c) Only surveying typical people

• d) Surveying coworkers

Random probability samples have great external validity because:

• a) They also ensure great internal validity

• b) They survey the entire population

• c) They use many measures

• d) All population members have an equal chance of being picked

When looking at a scatterplot showing two variables, an association is indicated when:

• a) The dots are clustered together

• b) There are a lot of dots on the graph

• c) The dots form a linear pattern

• d) The dots are randomly placed

Dr. Patel did a study on income level and life satisfaction in Chicago. She found those with higher income had higher life satisfaction. What must she consider to determine if this association is statistically significant?

• a) Sample diversity and number of questions asked

• b) Association direction and strength

• c) Sample size and effect size

• d) Outliers and association direction

Dr. Patel finds that higher income predicts greater life satisfaction. Her assistant says higher satisfaction causes higher income. What causal criteria did the assistant fail to meet?

• a) Time order

• b) Internal validity

• c) Construct validity

• d) External validity