Click on the icon ] on the bottom left corner of the applet above to display left-tailed probability.[br]Slide the left and right position markers on the x-axis to find the value of [math]z_1[/math] such that [math]P\left(X\le z_1\right)=0.9975[/math].
Click on the icon [ on the applet above to display right-tailed probability.[br]Slide the position marker on the x-axis to find the value [math]z_2[/math] such that [math]P\left(z_2\le X\right)=0.0025[/math]
What do you observe about the values [math]z_1[/math] and [math]z_2[/math]?
[math]P\left(X\le z_1\right)+P\left(z_1\le X\right)=...[/math]
In general, we have [math]P\left(X\ge z_0\right)=1-P\left(X\le z_0\right)[/math] for any real number [math]z_0[/math].