Did you read my tips on how to study and learn Stat 1000?  If not, here is a link to those important suggestions:

Did you read my Calculator Tips?  If not, here is a link to those important suggestions:

Did you see my tips for Assignment 1? Click here.

Did you see my tips for Assignment 2? Click here.

Did you see my tips for Assignment 3? Click here.

Study both Lesson 6: The Binomial Distribution and Lesson 7: The Distribution of the Sample Mean in my Basic Stats 1 book to prepare for this assignment.  NOTE: You need only study up to the end of question 7 (end of page 392) in Lesson 6 at this time (the rest of Lesson 6 will be covered after the second midterm).  You also need only study to the end of question 7 in Lesson 7 (end of page 447).  The section on control charts has been removed from the course.

I tell you the definitions of parameters and statistics at the start of Lesson 4 of my book and I repeat them again in Lesson 7 and illustrate with my question 1.

This is Lesson 7 stuff.  You have to always be asking yourself, "Is the problem talking about one individual score X? Or, is it talking about the mean of n scores, x-bar?"  If it is talking about just one score X, is X normally distributed?  If it is talking about the mean of n scores, x-bar, can we assume x-bar is normally distributed?  Why or why not?  If we can assume these are normally distributed, then be careful to use the proper standardizing formula.  Either the X-Bell Curve formula or the x-Bar Bell Curve formula.

Look at my questions 4 through 7 in Lesson 7 for examples.  Especially take note of my questions 6 and 7 if they give you a total amount in a question as they do in part (c).

When computing things like sigma/ square root n, make sure you round off to no less than 4 decimal places.  Better yet, store the exact value in the memory of your calculator. 

In part (c), be sure that you do not round off your answers for the sample mean too much.  Again, use at least 4 decimal places in your answers.  Better yet, don't even round off at all.  If the total is 179 and n is 13, just say x-bar is 179/13 and leave it like that.  Put 179/13 in for x-bar in your standardizing formula.  The calculator will handle that just fine, and you will get a more accurate answer for z.

Your probabilities are exact if you know for sure that the distribution is normal.  However, if you were only able to say the distribution is approximately normal, then your probabilities are only approximate.  This question boils down to, "Were you told the population is normal?"  If you know for a fact that the population is normal, you can compute exact probabilities.  If you do not, the best you can do is compute approximate probabilities (if you can compute the probability at all).

Approach this just like the previous question.  Ask yourself the same questions.

Lesson 6.  If you are ever asked to decide if a particular situation is binomial or not, remember, to be binomial, four conditions must be satisfied:

1. There must be a fixed number of trials, n.
2. Each trial can have only two possible outcomes, success or failure, and the probability of success on each trial must have a constant value, p.
3. Each trial must be independent.
4. X, the number of successes, is a discrete random variable where X = 0, 1, 2, ... n.

• If you are reading off numbers from a randomly selected row in the random number table, note that every row has 40 digits.  That is like 40 trials looking for whatever digit you may be looking for.  What is the probability that, at any moment on the table, the next digit is a 0, or a 1, or a 2, etc..
• If you are selecting objects, are you sampling with replacement (independent trials) or without replacement (dependent trials)?
• If you are given a Normal population, but are selecting a sample of size n, and want to see how many of them are greater than 62 (for example), THAT IS A BINOMIAL DISTRIBUTION!  You can use Table A to find what proportion are greater than 62.  That is your p.  Each trial, the person/thing either is greater than 62, or they are not.  And the chance they are greater than 62 is p, the proportion you shaded on the bell curve.
• If you are ever conducting trials until you get a desired result, that will never be binomial because you do not have a fixed number of trials, n.  For example, if I am rolling a die until I get a six and X= the number of rolls until I get a six, that is not binomial, because there are no fixed number of trials, n.
  
• Look at my solutions to your practice midterms (if you have them).  There are similar questions in both exams which will give you more insight.
  

Lesson 6 binomial stuff.

Be careful that you are using the correct n and p for each question since they keep switching which colour of M&M they are talking about and how many M&M's they are selecting. 

I am pretty sure that these two parts are covering a topic that is not included on your midterm exam (judging from your sample exams), so you may want to wait until after the exam before doing this part of the assignment.

These are p-hat bell curve questions.  Be sure you have studied The Distribution of the Sample Proportion p-hat (starts on page 404) in my book and look at my question 10 to prepare for this problem.

Be careful!  Do not round off too much when computing z scores for a p-hat bell curve.  I suggest that, when you work out the square root in the denominator of the p-hat bell curve formula, keep every single decimal place that your calculator gives you (or, better yet, store the result in a memory).  Then, you can expect your z score to be accurate to the 2 decimal places you will round it off to in the end.

Another question similar to my Lesson 6, question 10.  They are trying to confuse you as to what n is, so be careful.  Part (c) is also trying to confuse you.  It is similar to my 10(d).  What does p-hat have to be for there to be enough desks for left-handers in the class?