April 26 2018

(1). The table shows the weekly profit in naira from a mini market

Weekly(profit)

frequency

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)

frequency

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”

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