New York State would like to test of the Common Core method to see how many students are passing using this system. What is the probability that they obtain a SEM of 60 points, using the population descriptive statistics of  a µ=72 and a standard deviation of 4 points? You will need to find the z score but, first draw the normal curve and shade in the area that they are interested in finding.

Christopher has collected data to find that the total snowfall per year in Laytonville has a normal distribution. What is the probability that in a randomly selected year, the snowfall was greater than 53 inches if the mean is 92 inches and the standard deviation is 13 inches? Use the empirical rule.

The sample mean X is to be used to estimate the mean u of a normal distribution with standard deviation 4 inches. How large a sample should be taken in order chat, with 90% probability, the estimate will be in error by at most one-half inch?

The chart to the right shows that a professor's grading distribution is bell shaped, or normally shaped. The mean of the distribution is 74 and the standard deviation is 9. Using a Continuous Variable Normal Bell Distribution Model, calculate the minimum test score needed to score in the top 5% of the class. Complete your work in the worksheet by listing the formula inputs, labels for the formula inputs and make your calculations with formulas. This test problem is similar to what you studied in video # 32, 33 and 34 and homework problems # 17, 21 and 23. Relative Frequency Frequency Professor looks at all test score for a particular test (this is population data), and observes: 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Mean = 74 Median = 74 Mode = 73 SD=9 0 0 0 up to 10 up 10 to 20 0 20 up to 30 0 30 up to 40 2 40 up to 50 29 50 up to 60 X = Score 112 60 up to 70 225 70 up to 80 111 80 up to 90 21 2 90 up 100 up to 100 to 110

You are part of a trivia team and have tracked your team's performance since you started playing, so you know that your scores are normally distributed with u = 76 and o = 12. Recently, a new person joined the team, and you think the scores have gotten better. The sample data is n = 12, sample mean = 86 Assuming a one tailed test, What is the test statistic?

Deanna is the principal at a Midwestern middle school and wants to know the average IQ of all female, seventh grade students.  She does not know anything about what the population distribution looks like.  She took a simple random sample of 31 seventh-grade girls in her school and found the average IQ score in her sample was 105.8 and the standard deviation was 15. Using the sample standard deviation above to estimate the population standard deviation, what is the minimum sample size needed for a 99.5% confidence interval to have a margin of error of no more than 2.3?

How can get the standard deviation within the measures of dispersion or variability ?