Decide whether the sampling method could result in a biased sample. Write yes or no, and explain your reason.

1. A west coast based lawn service is trying to figure out how much water people use on average each month to water their lawn. They send surveys to people in Phoenix, Arizona and Seattle, Washington to compile this data.

2. Asking people in a library about the number of magazines to which they subscribe to in order to describe the reading habits of a town.

Decide whether the situation is an experiment or an observational study. Give at least one reason.
3. A teacher plays music during all tests given in a one-month period and compares the class grades with a similar class that does not have music played during tests.

4. A real estate developer records the listing and selling prices of all homes in one area to determine the difference in the listing price and the selling price.

It appears that people who are mildly obese are less active than leaner people. one study looked at the average number of minutes per day that people spend standing or walking. among mildly obese people, the mean number of minutes of daily activity (standing or walking) is approximately normally distributed with mean 376 minutes and standard deviation 64 minutes. the mean number of minutes of daily activity for lean people is approximately normally distributed with mean 528 minutes and standard deviation 107 minutes. a researcher records the minutes of activity for an srs of 7 mildly obese people and an srs of 7 lean people. use z-scores rounded to two decimal places to answer the following: what is the probability (image for it appears that people who are mildly obese are less active than leaner people. one study looked at the averag0.0001) that the mean number of minutes of daily activity of the 6 mildly obese people exceeds 420 minutes? what is the probability (image for it appears that people who are mildly obese are less active than leaner people. one study looked at the averag0.0001) that the mean number of minutes of daily activity of the 6 lean people exceeds 420 minutes?