Question

The United States has hosted foreign heads of state from 49 countries who have made 116 speeches before Congress. The Table includes data on those countries whose leaders have made four or more appearances. Assume this table includes the full population of appearances to keep the number of cases small for the calculation. Using the table, calculate a z score and use the z score to find the probability of leaders from a country delivering seven or more speeches before Congress.

COUNTRY NUMBER OF SPEECHES

United Kingdom 8

Israel 8

Mexico 7

France 7

Italy 6

South Korea 6

Ireland 6

Germany 5

India 4

Draw and label the distribution, shade the area of interest under the curve, include the X and Z scales.

Answer 1

z = (X - mu)/sigma

	X	Z
	8	1.3363
	8	1.3363
	7	0.5345
	7	0.5345
	6	-0.2673
	6	-0.2673
	6	-0.2673
	5	-1.0690
	4	-1.8708
mu	6.333333
sigma	1.247219

Formulas

	X	Z
	8	=(B2-6.333333)/1.247219
	8	=(B3-6.333333)/1.247219
	7	=(B4-6.333333)/1.247219
	7	=(B5-6.333333)/1.247219
	6	=(B6-6.333333)/1.247219
	6	=(B7-6.333333)/1.247219
	6	=(B8-6.333333)/1.247219
	5	=(B9-6.333333)/1.247219
	4	=(B10-6.333333)/1.247219
mu	=AVERAGE(B1:B10)
sigma	=STDEV.P(B1:B10)

P(X >= 7)

= P(X > 6.5)

= P(Z > (6.5 - 6.33333)/1.247219)

= P(Z > 0.13363 )

= 0.4468