Answer: option D
Step-by-step explanation:
The formulae for standard error = standard deviation/√n
But population standard deviation = 1.8 and sample size = n = 81
Standard error = 1.8/√81 = 1.8/9 = 0.2
Answer:
23 1/2 or 47/2
Step-by-step explanation:
it just is
Number 1 is A, number 2 is B number three is D
Answer:
5
Step-by-step explanation:
→ Let x = √20 + √20 .....
x
→ Square both sides
x² = 20 + √20 +√20 + √20
→ Replace √20 +√20 + √20 with x
x² = 20 + x
→ Move everything to the left hand side
x² - 20 - x = 0
→ Factorise
( x + 4 ) ( x - 5 )
→ Solve
x = -4 , 5
→ Discard negative result
x = 5
