Binomial Probability Distribution

Which of the following graphs represents a binomial distribution with n = 20 and p = 0.25?

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It is known that 75 percent of all households in the United States have intermittent Internet connectivity problems. For random samples of 450 independent households in the United States, what are the mean, μ, and standard deviation, σ, of the distribution of the number of households that have intermittent Internet connectivity problems?

Suppose 39% of Americans will vote for Donald Trump on election day. If a random sample of 8 voters are selected, what is the probability that 6 or more will vote for Trump?

• .9635

• .0365

• .9561

• .0439

A survey found that 25% of pet owners had their pets bathed professionally rather than do it themselves. If 18 pet owners are randomly selected, find the probability that exactly 5 people have their pets bathed professionally

• 3.42

• 1.03

• 0.072

• 0.199

The student who makes the morning announcements has the bad habit of saying “like” all the time. The chance that they say “like” in a sentence is 60%. You decide to keep a tally of how many times they say like. If they say 350 sentences this week, what is the probability that they will say “like” at least 200 times?

• 0.87

• 0.13

• 0.85

• 0.15

True or False:

exactly = binompdf

at most = binomcdf

at least = binomcdf

• True

• False

If you were to flip a coin 20 times, what is the probability you would get at most 13 heads?

• .9423

• .1316

• .0577

• .0739

In Vietnam, the probability of rain is 70%.  Find the probability of it raining at most 2 days in a week.

• .9712

• .0250

• .0287

• .2988

In Vietnam, the probability of rain is 70%.  Find the probability of it raining at most 5 days in a week.

• .9712

• .6705

• .3294

• .5520

A research team at Cornell University conducted a study showing that approximately 10% of all businessmen who wear ties wear them so tightly that they actually reduce blood flow to brain, diminishing cerebral functions. At a board meeting of 20 businessmen, all of whom wear ties, what is the probability that at least one tie is too tight?

• 27.0%

• 12.2%

• 73.0%

• 87.8%