Sampling Distribution of Proportions (p-hat) Practice

The true proportion of people who support a political candidate is p=0.52 and 2000 people are surveyed. We want to determine the probability that the results of the survey will suggest the candidate is losing the election (getting less than 50% of the votes). What is the Z-Score?

-1.79

If the true proportion of people who support a political candidate is p=0.52 and 2000 people are surveyed, what is the standard deviation of the sample proportions?

.011

Brittnie's batting average is 0.300. We want to determine the probability she will get more than 35 hits in her next 100 at bats. The standard deviation of sample proportions is ______.

.0458

Brittnie's batting average is 0.300. What is the probability of at least 35 hits in her next 100 bats?

.126

First Data Corp. records indicate that in 2005, 43% of adult email users received a phishing email. A phishing email replicates an authentic site for the purpose of stealing personal information such as account numbers and passwords. Suppose a random sample of 800 adults will be surveyed on whether they have received phishing emails to determine recent trends. Find the standard deviation of the sample proportions.

0.018

The true proportion of people who support a political candidate is p=0.52 and 2000 people are surveyed. Determine the probability that the results of the survey will suggest the candidate is losing the election (getting less than 50% of the votes).

0.037

A geneticist takes a simple random sample of n=140 gamete (sex) cells from the testes of a dog to determine the proportion which contain the chromosomes for development into a male. Assume the (unknown) true proportion of dog gametes that contain the male chromosome is 46%. What is the standard deviation of the sample proportions?

0.042

Brittnie's batting average is 0.300. We want to determine the probability she will get more than 35 hits in her next 100 at bats (n=100 and p=0.3) What is p-hat?

0.35

First Data Corp. records indicate that in 2005, 43% of adult email users received a phishing email. A phishing email replicates an authentic site for the purpose of stealing personal information such as account numbers and passwords. Suppose a random sample of 800 adults will be surveyed on whether they have received phishing emails to determine recent trends. Find the mean of the sample proportions.

0.43

A geneticist takes a simple random sample of n=140 gamete (sex) cells from the testes of a dog to determine the proportion which contain the chromosomes for development into a male. Assume the (unknown) true proportion of dog gametes that contain the male chromosome is 46%. What is the mean of the sample proportions?

0.46

Brittnie's batting average is 0.300. We want to determine the probability she will get more than 35 hits in her next 100 at bats. Z-score?

1.087

What is the 10% condition for variability?

10n ≤ N

If p = 1/4, what is the smallest n that satisfies the requirement for Normal distribution?

40

The geneticist conducts her survey and calculates p-hat=0.512. Which of the following is the most correct interpretation of this statistic?

51.2% of the gametes in the sample have the male chromosome.

Is p the true proportion or the sample proportion?

True Proportion

What is the difference between a bar chart and a histogram?

bar chart represents categorical variable; histogram represents quantitative variable.

What is the Normal condition requirement for sample proportions?

np≥10 and n(1−p)≥10

What is p-hat?

the sample proportion