Exam 9: Using Probability to Make Decisions About Data

The introductory biology class at State University is conducting a study of water quality in their local community.The population mean of a certain beneficial bacteria found in drinking water ( )is 100,with .The bacteria counts from the community are given below.Use a two-tailed rejection region with a total area of 0.05.What should you conclude?

There are 26 red cards in a playing deck and 26 black cards.The probability of randomly selecting a red card or a black card is 26/52 = 0.50.Suppose you randomly select a card from the deck five times,each time replacing the card and reshuffling before the next pick.Each of the five selections has resulted in a red card.On the sixth turn,the probability of getting a black card

If we decide not to reject the idea that a sample represents a particular population,because the sample mean does not lie within the rejection region,

Which of the following is not true of the criterion?

A cognitive psychologist tested whether people spend more time looking at and comprehending content words (e.g. ,ball,kick)than other words (the,a)when reading a passage.The mean looking time for a sample of content words was compared to the mean looking time for the population of other words by transforming it into a z-score.The z-score for the sample mean was z = 3.00.With critical values of 1.96,what should the psychologist conclude about the sample mean?

Which of the following is the criterion that psychologists usually use to determine the likelihood that a sample mean was obtained by chance?

The president of State College wants to conduct a survey of the students.He knows there are 325 freshmen,250 sophomores,175 juniors,100 seniors,and 150 graduate students.What is the probability that the very first person randomly selected for the survey will be a freshman?

What is the critical value?

The criterion determines

Suppose you take a piece of candy out of a jar,look to determine its color,then put it back into the jar before you randomly select the next piece of candy.This type of sampling is called

At a basic level,when deciding whether a sample is representative of a particular population,we

We create the sampling distribution of means from

Two events are said to be independent when

What do we call that portion of the sampling distribution in which values are considered too unlikely to have occurred by chance?

Your professor told the class that,typically,20% of the class receives As,20% Bs,35% Cs,10% Ds,and 15% Fs.What is the probability that the student sitting next to you will receive an A or an F?

As a general rule,when statisticians determine the probability of events,they assume that the events are _____ and sampled _____ replacement.

In a test of physical fitness,a group of men ages 65 and older from a local retirement community were told to do as many sit-ups as they could.It is known that the population mean is 20 with .The scores for the men from the retirement community are given below.Use a two-tailed rejection region with a total area of 0.05.What should you conclude?

The purpose of probability and inferential statistics is to

What can we conclude when the absolute value of a z-score for a sample mean is larger than the critical value?

If the probability of getting a z-score between the mean and +1 standard deviation is 0.3413,what is the probability of getting a z-score lower than 1 standard deviation?