STATISTICS(LECTURE 2)

April 03, 2020

LESSON 2: STATISTICS
DEAR STUDENTS

If yesterday was a good day, don’t stop. Maybe your winning streak has just begun.
Good morning one and all!!

Yesterday we covered the following learning outcomes:
RECALL THE DIFFERENT WAYS IN WHICH DATA CAN BE WRITTEN

Let us go through the guidelines for the blog once again:

• The text in Red, is to be written in your register

• The text in blue is to be viewed by clicking on it

• The text in green is to be practiced for home work

In class IX you have learnt to represent the data pictorially in the form of bar graphs, histograms and frequency polygons. In fact, you went a step further by studying certain numerical representatives of the ungrouped data, also called measures of central tendency, namely, mean, median and mode. In class X we shall extend the study of these three measures, i.e., mean, median and mode from ungrouped data to that of grouped data.

Please write the learning outcomes as mentioned below :

I will be able to:
1.RECALL WHAT IS MEASURE OF CENTRAL TENDENCY.
2. DEFINE MODE OF THE GIVEN DATA
3. CALCULATE MODE OF THE GIVEN DATA

let's do a quick revision :
WHAT IS MEASURE OF CENTRAL TENDENCY? ☟☟

WE WILL DISCUSS MODE TODAY!!

2. What is mode?

2. How do we find mode in the case of raw data?

3. Can there be more than one mode?

Look at the image given below, you will be able to find all the answers here

⭐⭐

👉What happens,if the data being analyzed is qualitative?

eg The hair colors of players on a football team, the color of cars in a parking lot,

🌟then the measure of central tendency that can be reported is the mode.

How to find mode (FOR UNGROUPED AND GROUPED DATA)?

CLICK on the LINK

Have you been through the link?

Now, Look at the table given below and calculate its mode.

The mode is....................(⭐Hint: find out the value which has the highest frequency)

FINDING MODE OF THE GROUPED DATA

FORMULA TO CALCULATE MODE OF THE GROUPED DATA(TAKE IT DOWN IN

THE NOTEBOOK)

NOW, LOOK AT THE GROUPED DATA GIVEN BELOW:(make a note of this )

1. What is the highest frequency in the data? Ans..................

2. Which is the modal class? Ans.............(look at class with highest frequency)

3. What is h=.........(find the difference between upper and lower limit , it will be same for all classes)

4. what is f1 =………(write the frequency of the modal class)

5.What is f0=………( write the frequency just before f1)

6. what is f2=……..(write the frequency just after f1)

7. what is L= …….(write the lower limit of the modal class you got in step 2)

⭐ In exams, substitution of correct values is given more weightage than just writing the formula

Now, note down question 1 of ex 14.2 in your notebook

Q1The following table shows the ages of the patients admitted in a hospital during a year:

Find the mode of the data given above. Interpret the measure of central tendency.

INTERPRETATION :MAXIMUM PATIENTS IN THE HOSPITAL ARE OF AGE 36.8 YEARS.

SOME IMPORTANT QUESTIONS☟(note them down in the notebook)

EG1

I hope you have gone through this question, now tell me what will you find 'mean' or 'mode' ?

The words 'average ' and ' maximum' in the same sentence are creating confusion.

Remember , in this type of question you will find 'MODE'

NOW ,YOU ATTEMPT THIS AS C.W (ANSWER IS 167.35cm)

EG2. NOTE DOWN THE QUES. GIVEN BELOW

AFTER SOLVING,THE VALUE OF X=..............

EG3 LOOK AT THE DATA GIVEN BELOW AND FIND ITS MODE.(NOTE IT DOWN)

NO. OF PLANTS	0-4	4-8	8-12	12-16	16-20
NO. OF HOUSES	11	10	7	4	3

In the above question, modal class is 0-4

so, f1 = 11

f2 = 10

but, what about f0? As there is no class just before modal class, f0 =0

Now,solve this question as HW

NOTE: IF MODAL CLASS IS THE LAST CLASS THEN F2=0

NOW, YOU CAN COMPLETE EX 14.2 AS H.W IN NEXT 2 DAYS!!
IN Q3 AND 4,CALCULATE ONLY MODE. MEAN WILL BE DONE LATER.

BEFORE YOU END THE CLASS, JUST TRY YOUR HAND AT THESE :