Question

(a) Approx. Kate the population mean and standard deviation of age for males. Male and female populations of elephants under 80 years old are represented by age in the table below. Complete parts (a) through (d) UE (Round to two decimal places as needed.) A (Round to two decimal places as needed.) (b) Approximate the population mean and standard deviation of age for females. Age -9 10-19 20-29 30-39 10-49 50-59 50-69 70-79 Males 14 13 12 17 24 24 15 14 Females 10 1 12 15 22 23 10 13 (Round to two decimal places as needed.) (Round to two decimal places as needed.) (c) Which gender has the higher mean age? have the higher mean age. (d) Which gender has the higher dispersion in age? have the greater dispersion

Answer 1

	males x	females y	(x-avgx)^2	(y-avgy)^2
	14	10		6.891		27.563
	13	7		13.141		68.063
	12	12		21.391		10.563
	17	19		0.141		14.063
	24	22		54.391		45.563
	24	23		54.391		60.063
	15	16		2.641		0.563
	14	13		6.891		5.063
sum	133	122		159.875		231.500
average	16.625	15.25
			variance	19.984		28.938
			stdev	4.470		5.379

1 For males, the population mean = 133/8 = 16.625

the population variance $\sigma^2 =\frac{\sum (x-avg(x))^2}{n}$

= 159.875/8 = 19.984

thus, std deviation $\sigma$ = sqrt(19.984) = 4.470

2. For females,the population mean = 122/8 = 15.25

the population variance $\sigma^2 =\frac{\sum (y-avg(y))^2}{n}$

= 231.5/8 = 28.938

thus, std deviation $\sigma$ = sqrt(28.938) = 5.379

3. Males have a higher mean age

4. Females have higher dispersion in age