Sophia Intro to Stats Unit 1 Milestone 1

Sophia Intro to Stats Unit 1 Milestone 1.A hunter is practicing his aim using a practice target. He takes 5 shots. All 5 shots hit the target, but they do not hit or surround the bullseye. In addition, all 5 shots are very spread apart on the target. Classify the hunter's accuracy and precision. Low accuracy and low precision High accuracy and low precision Low accuracy and high precision High accuracy and high precision RATIONALE Since the arrows fall away from the bullseye and are spread out we would classify this as low accuracy and low precision. CONCEPT Accuracy and Precision in Measurements 2 A team of researchers want to measure the distance covered while driving compared to a car's driving speed. Which statement is correct? The speed of the car is a confounding variable. The speed of the car is a dependent variable. The speed of the car is an explanatory variable. The speed of the car is a response variable. RATIONALE The outcome is the response, dependent or y -variable. The variable that explains the response is the explanatory, independent or x-variable. In this case the explanatory variable is speed with distance being the response. CONCEPT Variables 3 Which of the following data types will be continuous? The number of cars in 100 households The total weight of apples harvested in the farm in a season The letter grades students received on a class quiz The number of children younger than ten that visited a planetarium last week RATIONALE The total weight of apples can take on any value and is therefore continuous. The other measures can only take on a limited number of values and are discrete. CONCEPT Discrete vs. Continuous Data 4 Researchers want to study the effects of classical music and memory. One group of participants will take a memory test with classical music playing in the background, while the other group will take the memory test in complete silence. It is believed that age has an effect on memory. Which of the following would work best to test if classical music has an effect on memory? A completely randomized design experiment A matched-pair design experiment A case-control observational study A randomized block design experiment RATIONALE In order to control for age in the study, by matching participants on age they can control for the affect of age on the outcome. So a matched-pair design would be most appropriate. CONCEPT Matched-Pair Design 5 A grocery store owner asked the first 20 children who visited the store one day about their favorite snack. This is what type of sampling? Stratified sampling Convenience sampling Systematic sampling Voluntary response sampling RATIONALE Recall that convenience samples are samples taken due to their ease of gathering information. Since he simply asked the first 20 children, this is an example of that. Convenience samples are generally biased as they probably don't represent the entire set of interest.