Dear OTA,
Help me with the attached Problems.
Thanks

13. The mean amount of gasoline and services charged by Key Refining Company credit customers is $70 per month. The distribution of amounts spent is approximately normal with a standard deviation of $10. What is the probability of selecting a credit card customer at random and finding the customer charged between $70 and $83?

14. A statistics student receives a grade of 85 on a statistics midterm. If the corresponding z-score equals +1.5 and the standard deviation equals 7, what is the average grade on this exam?

15. A sample of 500 evening students revealed that their annual incomes from employment in industry during the day were normally distributed with a mean income of $30,000 and a standard deviation of $3,000. How many students earned more than $30,000?

16. A group of statistics students decided to conduct a survey at their university to find the average (mean) amount of time students spend studying per week. Based on a simple random sample, they surveyed 144 students. The statistics showed that students studied an average of 20 hours per week with a standard deviation of 10 hours. What is the standard error of the mean? 10

17. The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability that a person would score 130 or more on the test?
.9772

18. Truck tire life is normally distributed with a mean of 60,000 miles and a standard deviation of 4,000 miles. What is the probability that a tire will last 72,000 miles or more? 0.9987

... 3))=P(-0.54<Z<0.54)=0.4108 from normal table ...means, and draw a dotplot for sampling distribution of the ... create one plot with the sampling distributions for each ...

... He believes that the normal distribution well describes the distribution of publication ... of pages 100 300 500 700 900 1100 Probability 0.05 0.10 ...

...Normal Probabilities. ...Mean 100 2 Standard Deviation 2 ty for a Range 95 Probability for X ... Page 8 Given a normal distribution with a population mean of 100, a ...

Basic Statistics: Mean, Standard Deviation, Probability, Normal Distribution. ... possibly occur, then the probability of the ... the sum of the probabilities of the ...

... be used to find probabilities for all normal distributions. ... 1 is referred to as the standard normal distribution. ... 0,1) and has the probability density function ...

... solution gives the step by step method for computing probabilities based on ...PROBABILITY. ... entrance examination in a recent year had a normal distribution with a ...

... strength, mean, standard deviation and probabilities of normally ... 1 25 Namely, it follows normal distribution with mean... b) Find the probability that ¯x exceeds ...

... on calculating the probability under the standard normal distribution. 1. The average annual rainfall in a certain region is normally distributed with a mean of ...

... IQ increases or decreases, the probability of a ... used to find probabilities for all normal distributions. A standard normal distribution is a distribution where ...