13.1 - 13.3 Practice

Which statement about data collection is most accurate?

• A survey about parenting styles given to every tenth student entering the library will provide unbiased results.

• An observational study allows a researcher to determine the cause of an outcome.

• Statistics allow us to make completely accurate predictions about all elements in a population.

• A survey collected from a random sample of students in a school can be used to represent the opinions of the school population.

The heights of the students at Central High School can be modeled by a normal distribution with a mean of 68.1 and a standard deviation of 3.4 inches. According to this model, approximately what percent of the students would have a height less than 60 inches or greater than 75 inches?

• 0.86%

• 1.26%

• 2.12%

• 2.98%

A group of high school students wanted to collect information on how many times per week students exercised. If they want the least biased results they should survey every fifth student at the school who is

• entering the gym

• in the junior class

• entering the library

• entering the building

A population is normally distributed with a mean of 23 and a standard deviation of 1.2. The percentage of the population that falls below 21, to the nearest hundredth, is

• 0.05

• 4.78

• 8.29

• 91.30

A researcher wants to study the effect of a new teaching method on student performance. Which type of study would best allow the researcher to determine causation?

• Observational study

• Survey study

• Experimental study

• Case study

If a dataset is normally distributed with a mean of 50 and a standard deviation of 5, what percentage of the data falls between 45 and 55?

• 34.13%

• 68.26%

• 95.44%

• 99.74%

Approximately what percent of normally distributed data lies within 1 standard deviation of the mean?

• 5%

• 68%

• 95%

• 2.5%

On the normal curve, approximately what percent of normally distributed data lies above +2σ?

• 5%

• 68%

• 95%

• 2.5%

Which symbol represents the population mean?

• μ

• σ

• S_x

Which symbol represents the population standard deviation?

• μ

• σ

• S_x