7-10-4

Confidence Intervals

Definition of Terms

C-Level : confidence level (0 <C-Level < 1)

σ1 : population standard deviation of sample 1 (σ1 > 0)

σ2 : population standard deviation of sample 2 (σ2 > 0)

List(1) : list where sample 1 data is located

List(2) : list where sample 2 data is located

Freq(1) : frequency of sample 1 (1 or list name)

Freq(2) : frequency of sample 2 (1 or list name)

o1 : sample mean of sample 1 data

n1 : size of sample 1 (positive integer)

o2 : sample mean of sample 2 data

n2 : size of sample 2 (positive integer)

Calculation Result Output

Left : interval lower limit (left edge)

Right : interval upper limit (right edge)

o1 : sample mean of sample 1 data

o2 : sample mean of sample 2 data

x1σn−1 : sample standard deviation of sample 1 (Displayed only for list format.)

x2σn−1 : sample standard deviation of sample 2 (Displayed only for list format.)

n1 : size of sample 1

n2 : size of sample 2

Example

list1 : { 154, 109, 137, 115, 140 } , population standard deviation : 15.5

list2 : { 108, 115, 126, 92, 146 } , population standard deviation : 13.5

Significance level : 5% ( = confidence level : 95%)

•Statistics Wizard Operation

(1)Input the data into [list1] and [list2] in the Stat Editor.

(2)On the menu bar, tap [Calc] and then [Interval].

(3)Select [Two-Sample ZInt] and [List], and then tap [Next >>].

(4)Input values.

(5)Select List(1) [list1], List(2) [list2], Freq(1) [1] and Freq(2) [1].

(6)Tap [Next >>].

uProgram, eActivity or Main Application

Command: TwoSampleZInt

Command Syntax

Syntax 1 (list format)

C-Level value, σ1 value, σ2 value, List(1), List(2), Freq(1) (or 1), Freq(2) (or 1) * “Freq” can be omitted. Doing so sets “1” for “Freq”.

Syntax 2 (parameter format)

C-Level value, σ1 value, σ2 value, o1 value, n1 value, o2 value, n2 value

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