Math 9, Lesson 8, 11/8/2015

Weidong Post in Fall 2015, Teaching info
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We have mid-term exam today. I will have the test results for you next week.

Good luck!

 

Math 9, Lesson 7, 11/1/2015

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Today is a review day, as we will have our midterm exam next time on 11/8. We go over what we have learned this semester so far.

There is no specific homework, but the student should go back to the old class notes and homework to prepare for the exam.

 

Math 9, Lesson 6, 10/25/2015

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Two events are called to be independent events if the occurrence or non-occurrence of one event does not affect the probability of the other event.

If A and B are independent events, the probability of both events A and B occurring is the product of their individual probabilities:

P(A and B) = P(A) * P(B)

With this, we can simplify tree diagrams when dealing with problems with multiple same items by simply marking their probabilities.

When two (or more) events are dependent to each other, we cannot use the product rule, but we can still use the tree diagrams to help us finding probabilities.

Homework:

Workbook Page 12, #6 – #10, #16 – #20.

 

Math 9, Lesson 5, 10/18/2015

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We start a new subject on probability. Students should have learned some basic concepts before about simple probability, the concept of a sample space with events consisting of some outcomes. In this chapter ,we study probabilities with multiple stages.

When a random experiment involves two stages, we can use a rectangular grid, called a probability diagram, to represent the sample space to help us find probabilities.

If a random experiment has two or more stages, we can use a tree diagram to represent the process, which should help us see all the possible outcomes and figure out the outcomes associated with a particular event.

We then talk about mutually exclusive events. In a sample space, two events are mutually exclusive if they cannot occur at the same time. If A and B are two mutually exclusive events, the the probability of A or B occurring is: P(A or B) = P(A) + P(B).

Homework:

Workbook Page 11, #1 – #5, #21.

 

Math 9, Lesson 4, 10/4/2015

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Today we review functions and graphs. We look at linear functions, quadratic functions, functions in the form of y = ax^n, where n = -2, -1, 0, 1, 2, and 3,  exponential functions y = ka^x, a > 0, and how to estimate the gradients of curves by drawing tangents.

Students should have learned these topics before and this is a review lesson to refresh their memories.

Homework: #1 – #12 from the pages below:

Page 1, Page 2, Page 3.

 

Math 9, Lesson 3, 9/27/2015

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We continue study of standard deviation. We first review the formula for ungrouped data and grouped data.

We apply the standard deviation to help analyze two data sets. While means can give us the picture of average, standard deviation helps us to determine how consistent the data are. For example, if we look at two sets of data representing two basketball players’ scores, the lower the standard deviation, the more consistent the player is.

Homework:

Workbook Page 2, #7, 8, 9, 10, 12, 14, 16.

 

Math 9, Lesson 2, 9/20/2015

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We study standard deviation. In statistics, we have learned using mean to find the average, and we have learned to use range and interquartile range to see the spread of the data. But both range and interquartile range are not very good as the tool to represent the spread of the data.

A better way is the measure called standard deviation:

Standard Deviation SD = sqrt(sum of (Xi – AvgX)^2/N)

where N is the total number of data, AvgX is the mean of the data. Xi – AvgX is called the deviation of Xi from the mean AvgX for each i = 1, 2, …, N

For a set of grouped data in the form of a frequency table, we have

Mean AvgX = sum of fx / sum of f

where x is the class mark of each class and f is the frequency of the corresponding class.

Standard Deviation SD = sqrt(sum of f(Xi – AvgX)^2 / sum of f)

[Sorry, I can’t type using the summation notation sigma, which is what we learn in the class. This will simplify the writing.]

Homework:

Page 1 from the Workbook, #1, #2, #3, #4, #5, #6.

Math 9, Lesson 1, 9/13/2015

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We have our first class today.

First thing first, each student should prepare two notebooks, one for taking the notes in the classroom, and one for doing the homework.

For this year, while we learn new material, we will also spend time reviewing what we have learned in the past. The review sessions will be mixed with the new lessons.

Today we review the topics of Algebraic Manipulation And Formulae. You can find the corresponding material in your Workbook on Page 72.

For homework, please download the following 4 pages and do the following: #3, #4, #5, #6, #7, #9, #11, #13, #14, #15, #18, #19, #20.

Page 1

Page 2

Page 3

Page 4

 

Welcome to Math 9!

Weidong Post in Fall 2015, Teaching info
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Welcome to Math 9. I will be the new teacher for this class this year.

From the student list, I see many familiar names, as I used to teach Math 7, and many students were in my class before.

I have updated my blog site to include the course information, teaching plan for Math 9. Please read.

As before, I will leave homework via my blog site each Sunday. Students should have their workbooks by now and the homework will be from that workbook.

I look forward to meeting your kids soon and feel free to contact me if you have any question.

 

Math 7A, Lesson 14, 5/31/2015

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First of all, congratulations to the following students in our class who have won in the recent school wide Math contest:

Karen Li is the sole 1st place winner in the  6th grade category with $20 prize.

Eugene Jiang, Robert Sheng, Alexander Deng, Jiming Xu are among other prize winners in the 6th grade category and will each get $10 prize.

Congratulations again!

Since we have finished covering the regular content in the textbook, I am adding a little more today. For the last two lessons, we will have review and final exam.

We study combinations and permutations, with the introduction of factorial. A combination is a group of outcomes where the order does not matter, while permutation is a group of outcomes where the order does matter. Factorial is a way of computation. The factorial of a number is the product of the number and all the natural numbers less than the number.

n! = n x (n-1) x (n-3) x … x 3 x 2 x 1

The number of permutations of choosing r things out of n things at a time is denoted as nPr and

nPr = n! / (n-r)!

The number of combinations of choosing r things out of n things at a time is denoted as nCr and

nCr = n! / [r! x (n-r)!]

Today’s material can be found here for Section 10.8.

Homework: download this page

Page 765, #12 – #23.