Final answer:
The null hypothesis assumes no significant difference or effect, while the alternative hypothesis states the opposite. The null and alternative hypotheses for the given scenarios are explained.
Step-by-step explanation:
The null and alternative hypotheses are statements used in hypothesis testing to determine the validity of a claim or statement. The null hypothesis, denoted as H0, represents the initial claim, assumption, or statement, and assumes that there is no significant difference or effect. The alternative hypothesis, denoted as Ha, states that there is a significant difference or effect.
In the given scenarios:
1. 180 crashes:
Null hypothesis (H0): The number of crashes within 5 miles of the crashing person's home is not significantly different from the expected value.
Alternative hypothesis (Ha): The number of crashes within 5 miles of the crashing person's home is significantly different from the expected value.
2. Times Square:
Null hypothesis (H0): The probability that a person picked at random in Times Square is visiting the area is 0.83.
Alternative hypothesis (Ha): The probability that a person picked at random in Times Square is visiting the area is not equal to 0.83.
3. Standard deviation of speeds:
Null hypothesis (H0): The standard deviation of speeds is not more than what was reported.
Alternative hypothesis (Ha): The standard deviation of speeds is more than what was reported.