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## How to Solve Statistics Using Casio fx991ms

GROUPED DATA
(1). The table shows the weekly profit in naira from a mini market
Weekly(profit)
1, 10, 11, 20, 21, 30, 31, 40, 41, 50, 51, 60
- - - - - - - - - - - -
frequency
6, 6, 12, 11, 10, 5
Find the mean (x)
(A) 30.1 (B)31.0 (C) 31.1 (D) 31.2
Find the variance
(A) 220.64 (B) 220.62 (C) 198.64 (D) 221.64
Find the standard deviation
(A) 14.85 (B) 14.86 (C) 15.80 (D) 15.85
Solution:-Using CASIO fx-991MS calculator
Divide the data “weekly(profit)” by 2
Weekly(profit)
5.5, 15.5, 25.5, 35.5, 45.5, 55.5
frequency
6, 6, 12, 11, 10, 5
Solution:-Imputing the data using CASIO
fx-991MS calculator
Press [ON] [5.5] [SHIFT] [;] [6] [M+] [15.5] [SHIFT] [;] [6] [M+] [25.5] [SHIFT] [;] [12] [M+] [35.5] [SHIFT] [;] [11] [M+] [45.5] [SHIFT] [;] [10] [M+] [55.5] [SHIFT] [;] [5] [M+]
Find the mean (x)
press [SHIFT] [S-VAR] [1] [=] (31.1) The correct option is “C”
Find the variance
press [SHIFT] [S-VAR] [2] [x² ] [=] (220.64) The correct option is “A”
Find the standard deviation
press [SHIFT] [S-VAR] [2] [=] (14.8539557) The correct option is “A”
SINGLE DATA
(2). The following data gives the lengths in cm of 30 pieces of iron rods 45, 55, 65, 60, 61, 68, 59, 54, 64, 70
Find the mean (x)
(A) 56.1 (B) 60.1 (C) 60.2 (D) 59.6
Find the variance
(A) 49.29 (B) 329.6 (C) 49.0 (D)46.89
Find the standard deviation
(A)7.02 (B) 7.03 (C)7.00 (D) -7.02
To operate the stastic calculation Using
CASIO fx-991MS calculator
Press [ON] [MODE] [MODE] [1] (SD) [45] [M+] [55] [M+] [65] [M+] [60] [M+] [61] [M+] [68] [M+] [59] [M+] [54] [M+] [64] [M+] [70] [M+]
Find the mean (x)
Press [SHIFT] [2] [1] (mean x) [=] (60.1)
The correct option is “B”
Find the variance
Press [SHIFT] [S-VAR] [2] [x2 ] [=] (49.29)
The correct option is option “A”
Find the standard deviation
Press [SHIFT] [S-VAR] [2] [=] (7.020683727) The correct option is “A”