If 9 of the sparrows is 45% of the birds in the backyard, 9/x = 45/100.
Cross multiply to get 9 * 100 = 45x; simplified is 900 = 45x or 20.
This means that there are 20 birds in the backyard. You can check this by dividing 9/20 which equals 45%
Answer:
x<-5 <--------o open circle
Step-by-step explanation:
Answer:
The height of the lighthouse is approximately 166.6 feet.
Step-by-step explanation:
Let the height of the lighthouse be represented by s, then;
Tan 48° = (opposite) ÷ (adjacent)
Tan 48° = s ÷ 150
⇒ s = 150 × Tan 48°
= 150 × 1.1106
= 166.59
s ≅ 166.6 feet
Therefore, the height of the lighthouse is approximately 166.6 feet.
Answer:
Step-by-step explanation:
Given that in an investigation of pregnancy-induced hypertension, one group of women with this disorder was treated with low-dose aspirin, and a second group was given a placebo. A sample consisting of 50 women who received aspirin has mean arterial blood pressure 120mmHg and standard deviation 10mmHg; a sample of 42 women who were given the placebo has mean blood pressure 115mmHg and standard deviation 12mmHg.
Population variances are equal

(two tailed test at 5% significance level)
Here x denotes group I and Y group II
N Mean StDev SE Mean
Sample 1 50 120 10 1.4142
Sample 2 42 115 12 1.8516
Pooled std deviation = 10.9565
df=80
Mean difference= 5
Test statistic t = mean diff/std error =
=2.1803
p value = 0.0318
since p <0.05 we reject H0
b) We find p >0.01 hence at 1% significance level we accept H0
This implies that 99% confidence interval contains mean difference =0