# Thread: Help with stats questions?

1. ## Help with stats questions?

Hi there, I'm really poor at doing probability and stats and it doesn't help that I can't afford the textbook for the course, however I have to complete these exercises for next week. Can anyone help me understand the equations of how I would go about completing these questions? I would really appreciate any help.

1. The amount of sodium in a randomly selected 9-ounce serving of chicken noodle soup has a normal distribution with mean 1106 mg and standard deviation 150 mg. Suppose an 8-ounce serving chicken noodle soup is randomly selected.

a. What is the probability that the amount of sodium is over 1000 mg?

b. What is the probability that the amount of sodium is between 800 mg and 1200 mg?

c. Given that the amount of sodium is over 1000 mg, what is the probability that it is
less than 1200 mg?

d. Find a symmetric interval about the mean such that 90% of all 8-ounce serving chicken
noodle soup have sodium amount in this interval.

2. Suppose that in a weekly lottery, you have 2% chance of winning a prize with a single ticket. Assume you buy only 1 ticket per week for 52 weeks.

a. What is the probability that you win no prizes?

b. What is the probability that you win 3 or more prizes?

c. What is the mean and standard deviation of the number of prizes you win?

d. What is the probability that the rest winning is in the sixth week?

2. Originally Posted by tropheus
Hi there, I'm really poor at doing probability and stats and it doesn't help that I can't afford the textbook for the course, however I have to complete these exercises for next week. Can anyone help me understand the equations of how I would go about completing these questions? I would really appreciate any help.

1. The amount of sodium in a randomly selected 9-ounce serving of chicken noodle soup has a normal distribution with mean 1106 mg and standard deviation 150 mg. Suppose an 8-ounce serving chicken noodle soup is randomly selected.

a. What is the probability that the amount of sodium is over 1000 mg?

b. What is the probability that the amount of sodium is between 800 mg and 1200 mg?

c. Given that the amount of sodium is over 1000 mg, what is the probability that it is less than 1200 mg?

d. Find a symmetric interval about the mean such that 90% of all 8-ounce serving chicken noodle soup have sodium amount in this interval.

2. Suppose that in a weekly lottery, you have 2% chance of winning a prize with a single ticket. Assume you buy only 1 ticket per week for 52 weeks.

a. What is the probability that you win no prizes?

b. What is the probability that you win 3 or more prizes?

c. What is the mean and standard deviation of the number of prizes you win?

d. What is the probability that the rest winning is in the sixth week?
If you don't have the book, don't understand the instructor, and have no idea even how to begin any portion of either exercise, then I'm afraid you need much more help than we can here provide. You may want to consider hiring a qualified local tutor who, by looking at your class notes (and perhaps being familiar with the instructor and the textbook), perhaps be able to provide you with the hours every week of personalized instruction you are requesting. Good luck!

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•