TEACHING STATISTICS Using the EL-W535HT

STAT mode on the EL-W535HT: 0: NORMAL 1: STAT 2: DRILL 3: TABLE <<STAT – 1>> 0:SD 1:LINE 2:QUAD 3:E_EXP 4:LOG 5:POWER Stat 0 [SD] 0. To access STAT mode: Then choose the type of statistics you want to do e.g. 0: SD (single data) The ALPHA button is used to access all the variables in STAT mode The (x,y) button is used for grouped data or linear regression The button is used to store data in STAT mode

<<STAT – 1>> To do any statistics calculations press press to choose STAT mode. The following screen will appear 0: SD is where you can do single data or grouped data calculations 1: LINE is where you can do linear regression calculations 2: QUAD is where you can do quadratic regression calculations <<STAT – 1>> 0:SD 1:LINE 2:QUAD 3:E_EXP 4:LOG 5:POWER

Variables available in STAT mode: Sample Standard Deviation of 𝑦 Population Standard Deviation of 𝑦 Sample Standard Deviation of 𝑥 Mean of 𝑦 To find 𝑎, 𝑏 and 𝑐 in LINE 𝑦=𝑎+𝑏𝑥 or QUAD 𝑦=𝑎+𝑏𝑥+𝑐 𝑥 2 Mean of 𝑥 Population Standard Deviation of 𝑥 Sum of 𝑥𝑦 Sum of 𝑦 Sum of 𝑦 2 Total Number of Terms Sum of 𝑥 Sum of 𝑥 2

Single Data To do single data calculations press press to choose STAT mode and press to choose SD. 8 people wrote a maths test out of 75 marks, their results are as follows: 69, 49, 60, 58, 70, 36, 73, 65

Single Data 69, 49, 60, 58, 70, 36, 73, 65 Simply enter the data by typing in the number and pressing the button after each entry For example: 69 Your screen will then say: 69DATA DATA SET = 1

69, 49, 60, 58, 70, 36, 73, 65 Continue to enter all the marks in the same way. If you make a mistake, you can press the up/down arrow keys ( / ) until you reach your mistake then re-enter the number and press again to store the correct data. Press to begin doing calculations.

𝑥 =60 𝜎𝑥=11.5974135 To calculate the mean: Press 4 To calculate the standard deviation: Press 6 𝜎𝑥=11.5974135 To calculate the sum of all the values entered: Press 𝑥 =480

To calculate the median First arrange the data from lowest to highest: 36, 49, 58, 60, 65, 69, 70, 73 To find the median use this formula: 𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛 = n+1 2 Press + 1 2 = 4.5 This tells us that the median is between position 4 and 5. So the median is between 60 and 65. 𝑚𝑒𝑑𝑖𝑎𝑛= 60+65 2 𝑚𝑒𝑑𝑖𝑎𝑛=62.5

To calculate the mean There are two methods to work out the mean: Method 1 To find the mean use this formula: Showing working out 𝑚𝑒𝑎𝑛= 𝑥 ÷𝑛 Press 480 Press 8 ∴𝑚𝑒𝑎𝑛=480 ÷8=60

To calculate the mean Method 2 There is a much easier way to calculate the mean if you do not need to show working out. Press 4 60 ∴𝑚𝑒𝑎𝑛=60

You can also use the statistics functions within a calculation: You are asked to calculate the coefficient of variance 𝐶𝑉= 𝜎 𝑥 Press ÷ 0.193 To show working out: 𝜎=11.597 𝑥 =60 So 𝐶𝑉= 11.597 60 =0.193

Make sure that your memory for the previous data is cleared before you enter your new data. To do this press: Remember that the calculator stores all your data until you purposefully clear the memory.

Grouped data The class writes a maths test out of 10, these are the marks obtained by the various students: 6, 5, 6, 7, 3, 9, 8, 5, 8, 6, 4, 9, 7, 6, 8, 7, 6, 6 Enter the data into a table to determine the frequency of each value. MARK OBTAINED FREQUENCY 3 1 4 5 2 6 7 8 9

Grouped data Ensure you are in the correct mode: MARK OBTAINED FREQUENCY 3 1 4 5 2 6 7 8 9 Ensure you are in the correct mode: Stat 0 [SD] 0.

Grouped Data MARK OBTAINED FREQUENCY 3 1 4 5 2 6 7 8 9 To enter the first data set Press 3 1 x-value is the mark obtained y-value is the frequency Enter each data set in this way. 3 , 1 DATA DATA SET = 1 3 , 3 3 , 1

Grouped Data MARK OBTAINED FREQUENCY 3 1 4 5 2 6 7 8 9 To calculate the mean: Press 𝑥 =6.44 OR (with working out) Press 116 Press 18 𝑥 =116 ÷18 All the other calculations are also done in the same way as with single data (by using to access any statistics function that you need).

Linear Regression You can calculate the formula for a straight line using two co-ordinate pairs. Press Stat 1 [LINE] 0.

Linear Regression To enter the data Press 7 , 4 DATA DATA SET = 2

Linear Regression If you look at the insert on the cover of your calculator you will see the equation used for 1: LINE…y = a + bx This is different to y = bx + c that teachers normally use because the a and the c have been swopped around. So: a is the y-intercept b is the gradient

Linear Regression To calculate the gradient: Press 0.5 To calculate the y – intercept: So the equation of the straight line graph is: 𝑦=0.5𝑥+0.5 𝒂= 0.5 𝒃= 0.5 7 , 4 DATA DATA SET = 2

Thank you for your time, I hope you enjoyed the presentation Thank you for your time, I hope you enjoyed the presentation. Don’t forget to check out our website www.mathsatsharp.co.za for free maths and math literacy worksheets, with memos, and study guides.