The given data below shows the time in intervals in seconds between successive white cars in flowing traffic in an open road.Can these be modeled by an exponential distribution.

I am computing the expected frequencies by calculating the probability at each interval.Under null hypothesis as this follows an exponential distribution for the first category I integrated from 0-20.

Then Expected frequency for that category is Probability total frequency=0.3935*100.

The lamda value for the exponential distribution is found by supposing this equals sample mean.

Sample mean=Sigma f*x/Sigma f.

If this data follows an exponential distribution with parameter lamda as expected value=

1/lamda=(Sigma f*x)/(Sigma f) .

My H0 is Data follows an exponential distribution

My question is when I calculate Expected frequencies though the total should add up to 100 it does not do so because of

Here should I need to add another category myself as the interval being 180-infinity and get its expected value as 100-98.89=1.11.

Is it necessary to add this category as this is an

I am computing the expected frequencies by calculating the probability at each interval.Under null hypothesis as this follows an exponential distribution for the first category I integrated from 0-20.

Then Expected frequency for that category is Probability total frequency=0.3935*100.

The lamda value for the exponential distribution is found by supposing this equals sample mean.

Sample mean=Sigma f*x/Sigma f.

If this data follows an exponential distribution with parameter lamda as expected value=

**1/lamda**,1/lamda=(Sigma f*x)/(Sigma f) .

My H0 is Data follows an exponential distribution

My question is when I calculate Expected frequencies though the total should add up to 100 it does not do so because of

**rounding off**errors right?I get a value of 98.89.Here should I need to add another category myself as the interval being 180-infinity and get its expected value as 100-98.89=1.11.

Is it necessary to add this category as this is an

**exponential distribution**which goes for infinity?Of course as the Expected value of the created category is less than 5, in this case I have to add this up with the upper category.But if I do not consider this new category then the degrees of freedom changes.Is it necessary to add this new category as**180-infinity**
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