The Amount of Time That a Student Brushes His Teeth

question 35

Short Answer

The amount of time that a student brushes his teeth has an approximate normal distribution with a
mean of 1.8 minutes and a standard deviation of 0.3 minutes. What is the probability that the student
brushes his teeth for less than 1.2 minutes? Give your answer as a percentage.

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Definitions:

Experiment

A method of investigation in the sciences or social sciences in which variables are manipulated to observe the effect on some behavior or condition.

Testable Prediction

A testable prediction is a specific statement about the expected outcome of a scientific experiment, based on a hypothesis or theory, that can be observed and measured.

Independent Variables

Variables in an experiment that are manipulated or changed to observe their effects on dependent variables.

Dependent Variables

In an experiment, the variable that is being measured or tested, expected to change as a result of manipulation of the independent variable.